A

a-

(word root) not, fromExamples of words with the root a-: asexual, atheist

A

abbr.1. accusative2. Games ace3. across4. adenine5. alto6. ampere7. or Å angstrom8. answer9. area10. Sports assist

a¹

or A E0058100 (ā)n. pl. a's or A's also as or As 1. The first letter of the modern English alphabet.2. Any of the speech sounds represented by the letter a.3. The first in a series.4. Something shaped like the letter A.5. A The best or highest in quality or rank: grade A milk.6. Music a. The sixth tone in the scale of C major or the first tone in the relative minor scale.b. A key or scale in which A is the tonic.c. A written or printed note representing this tone.d. A string, key, or pipe tuned to the pitch of this tone.7. A One of the four major blood groups in the ABO system. Individuals with this blood group have the A antigen on the surface of their red blood cells, and the anti-B antibody in their blood serum.Idiom: from A to Z Completely; thoroughly.

a²

O0000850 (ə; ā when stressed)indef.art.1. Used before nouns and noun phrases that denote a single but unspecified person or thing: a region; a person.2. Used before terms that denote number, amount, quantity, or degree: only a few of the voters; a bit more rest; a little excited.3. a. Used before a proper name to denote a type or a member of a class: the wisdom of a Socrates.b. Used before a mass noun to indicate a single type or example: a dry wine.4. The same: birds of a feather.5. Any: not a drop to drink.

[Middle English, variant of an, an; see an¹.]Usage Note: In writing, the form a is used before a word beginning with a consonant sound, regardless of its spelling (a frog, a university, a euphemism). The form an is used before a word beginning with a vowel sound (an orange, an hour). · An was once a common variant before words beginning with h in which the first syllable was unstressed; thus 18th-century authors wrote either a historical or an historical but a history, not an history. This usage made sense in that people often did not pronounce the initial h in words such as historical and heroic, but by the late 19th century educated speakers usually gave their initial h's a huff, and the practice of writing an before such words began to die out. Nowadays it survives primarily before the word historical. One may also come across it in the phrases an hysterectomy or an hereditary trait. These usages are acceptable in formal writing.

a³

O0000850 (ə)prep. In every; to each; per: once a month; one dollar a pound.

[Middle English, from Old English an, in; see on.]

a⁴

O0000850 (ə)aux.v. Informal Have: He'd a come if he could.

[Middle English, alteration of haven, to have; see have.]

a⁵

abbr.1. acceleration2. are (measurement)

a

(eɪ) or

A

n, pl a's, A's or As1. (Linguistics) the first letter and first vowel of the modern English alphabet2. (Phonetics & Phonology) any of several speech sounds represented by this letter, in English as in take, bag, calm, shortage, or cobra3. (Education) Also called: alpha the first in a series, esp the highest grade or mark, as in an examination4. from A to Z from start to finish, thoroughly and in detail

a

(ə; stressed or emphatic eɪ) determiner (indefinite article; used before an initial consonant) 1. used preceding a singular countable noun, if the noun is not previously specified or known: a dog; a terrible disappointment. 2. used preceding a proper noun to indicate that a person or thing has some of the qualities of the one named: a Romeo; a Shylock. 3. used preceding a noun or determiner of quantity: a cupful; a dozen eggs; a great many; to read a lot. 4. used preceding a noun indicating a concrete or abstract thing capable of being divided: half a loaf; a quarter of a minute. 5. (preceded by: once, twice, several times, etc) each or every; per: once a day; fifty pence a pound. 6. a certain; one: to change policy at a stroke; a Mr Jones called. 7. (preceded by not) any at all: not a hope.

a

(ə) vb an informal or dialect word for have: they'd a said if they'd known.

a

(ə) prep (usually linked to the preceding noun) an informal form of of: sorta sad; a kinda waste.

a

symbol for 1. (General Physics) acceleration 2. (Units) are(s) (metric measure of land) 3. (Units) atto- 4. (Chess & Draughts) chess See algebraic notation

A

symbol for 1. (Classical Music) music a. a note having a frequency of 440 hertz (A above middle C) or this value multiplied or divided by any power of 2; the sixth note of the scale of C majorb. a key, string, or pipe producing this notec. the major or minor key having this note as its tonic 2. (Biochemistry) a human blood type of the ABO group, containing the A antigen 3. (Automotive Engineering) (in Britain) a major arterial road: the A3 runs from London to Portsmouth. 4. (Film) (formerly, in Britain)a. a film certified for viewing by anyone, but which contains material that some parents may not wish their children to seeb. (as modifier): an A film. 5. (General Physics) mass number 6. (Mathematics) the number 10 in hexadecimal notation 7. (Card Games) cards ace 8. (Chemistry) chem argon (now superseded by Ar) 9. (Electronics) ampere(s) 10. (Electrical Engineering) Also: at ampere-turn 11. (General Physics) absolute (temperature) 12. (Electronics) (in circuit diagrams) ammeter 13. (Mathematics) area 14. (General Physics) (in combination) atomic: an A-bomb; an A-plant. 15. (Chemistry) chem affinity 16. (Biochemistry) biochem adenine 17. (Logic) logic a universal affirmative categorical proposition, such as all men are mortal: often symbolized as SaP. Compare E, I², O¹ 18. a. a person whose job is in top management, or who holds a senior administrative or professional position b. (as modifier): an A worker. See also occupation groupings abbreviation for (Automotive Engineering) Austria (international car registration) [from Latin a(ffirmo) I affirm]

Å

symbol for (General Physics) angstrom unit

A, a

(eɪ)

n., pl. A's As, a's as. 1. the first letter of the English alphabet, a vowel. 2. any spoken sound represented by this letter. 3. something shaped like an A. 4. a written or printed representation of the letter A or a. Idioms: from A to Z, from beginning to end; completely; thoroughly: He knows the Bible from A to Z.

a¹

(ə; when stressed eɪ)

indefinite article. 1. (used before a singular noun not referring to any specific member of a class or group or referring to a member not previously mentioned): We need a new car. I spoke to a doctor. 2. any; every: A dog has four legs. 3. one: a hundred years; a dozen eggs; a yard of fabric. 4. (used indefinitely with certain quantifiers): a great many years; a few stars. 5. the same: two at a time. 6. a single portion, unit, type, or instance of: two coffees and a tea. 7. a certain; a particular: A Mr. Johnson called. 8. another; one resembling: a Cicero in eloquence. 9. a work by: a Van Gogh. 10. any; a single: not a one. [Middle English; orig. preconsonantal phonetic variant of an¹] usage: In both spoken and written English a is used before words beginning with a consonant sound (a book), an before words beginning with a vowel sound (an apple). Words that start with vowel letters but are pronounced with the consonant sound (y) or (w) are preceded by a: a union; a European; a one-room apartment. The names of the consonant letters f, h, l, m, n, r, s, and x begin with a vowel sound and thus are preceded by an: an F in geometry; to fly an SST. The names of all other consonants and of the vowel u take a: a B in Spanish; a U-turn. Words that begin with the letter h sometimes cause confusion. When the h is not pronounced, the word is preceded by an: an hour. When h is pronounced, the word is preceded by a: a history of the Sioux; a hero sandwich. (Formerly, an was used before pronounced h:an hundred.) Usage is divided, however, with such words as historian, historical, heroic, and habitual, which begin with an unstressed syllable in which h may be weak or silent. The use of a is widespread in both speech and writing (a historian of ancient China; a habitual criminal), but an is also common. Hotel and unique are occasionally preceded by an, but this use is regarded as old-fashioned.

a²

(ə; when stressed eɪ)
prep. for or in each; for or in every; per: ten cents a ride; three times a day.[orig. Middle English a, preconsonantal variant of on (see a-¹); confused with a¹]usage: See per.

a³

(ə)
prep. Pron. Spelling. of (often written as part of a single word, without a hyphen): the time a day; kinda; sorta.[Middle English]

a⁴

(ə)
auxiliary verb. Pron. Spelling. have (often written as part of a single, unhyphenated word): We shoulda gone.[Middle English]

Å

Physics Symbol. angstrom.

A

1. ampere. 2. angstrom. 3. answer.

A

Symbol. 1. the first in order or in a series. 2. (sometimes l.c.) (in some grading systems) a grade or mark indicating excellence or superiority. 3. a. the sixth tone of the ascending C major scale. b. the tonality having A as the tonic. 4. a major blood group. Compare ABO system. 5. adenine. 6. alanine. 7. (formerly) argon. 8. mass number.

a

are (unit of measurement).

A-

atomic (used in combination): A-bomb; A-plant.

a-¹

, a reduced form of the Old English preposition on, meaning “on,” “in,” “into,” “to,” “toward,” preserved before a noun or adjective in a prepositional phrase, forming a predicate adjective or an adverbial element (afar; afoot; aloud; ashore; away). By analogy with original nominal collocations, a-¹ has been joined to verbs, the resulting formation having the force of a present participle (ablaze; astride; awash). [Middle English, late Old English; compare a², nowadays]

a-²

, a reduced form of the Old English preposition of: akin; afresh.

a-³

, a verbal prefix with the historical sense “out, up,” occurring in verbs and verb derivatives inherited from Old and Middle English, usu. marking the inception or completion of the action denoted by the base verb: abide; accursed; arise; ashamed; awake.[Middle English; Old English]

a-⁴

, var. of ab- before b, m, and v: amanuensis; avert.[Middle English < Latin ā-, a-]

a-⁵

, var. of ad-, used before sc, sp, st (ascend) and in words of French derivation, often with the sense of increase or addition (amass). [Middle English, in some words < Middle French a- < Latin ad- prefix or ad preposition (see ad-), as in abut; in others < Latin a- (variant of ad- ad-), as in ascend]

a-⁶

, var. of an-¹ before a consonant: amoral; atonal; achromatic.

-a¹

, a plural ending of nouns borrowed from Greek and Latin: phenomena; criteria; data.

-a²

, a feminine singular ending of nouns borrowed from Latin and Greek, also used in New Latin coinages to Latinize bases of any origin, and as a Latin substitute for the feminine ending -ē of Greek words: cinchona; pachysandra.

-a⁴

, a suffix occurring in the names of oxides of the chemical element denoted by the stem: alumina; thoria.[probably <-a of magnesia]

A.

1. Absolute. 2. Academy. 3. acre. 4. America. 5. American. 6. year. [< Latin annō, abl. of annus] 7. before. [< Latin ante] 8. April.

a.

1. about. 2. acre. 3. active. 4. adjective. 5. alto. 6. ampere. 7. year. [< Latin annō] 8. anonymous. 9. answer. 10. before. [< Latin ante] 11. are (unit of measurement). 12. Baseball. assist; assists.

A

Abbreviation of area

a

an">an1. 'a' and 'an'

You usually use a and an when it is not clear or important which specific thing or person you are referring to. You only use a and an with singular countable nouns. When you are talking about a specific person or thing, you usually use the.

She decided to buy a car.He parked the car in front of the bakery.See the

You can describe someone or something using a or an with an adjective and a noun, or with a noun followed by more information.

His brother was a sensitive child.The information was contained in an article on biology.

Be Careful!
Don't omit a or an in front of a noun when the noun refers to someone's profession or job. For example, you say 'He is an architect'. Don't say 'He is architect'.

She became a lawyer.2. 'a' or 'an'?

You use a in front of words beginning with consonant sounds and an in front of words beginning with vowel sounds.

Then I saw a tall woman standing by the window.We live in an old house.

You use an in front of words beginning with 'h' when the 'h' is not pronounced. For example, you say 'an honest man'. Don't say 'a honest man'.

The meeting lasted an hour.

An is used in front of the following words beginning with 'h':

heirheiressheirloomhonesthonoraryhonourhonourablehourhourly

You use a in front of words beginning with 'u' when the 'u' is pronounced /juː/ (like 'you'). For example, you say 'a unique occasion'. Don't say 'an unique occasion'.

He was a university professor.She became a union member.

A is used in front of the following words:

ubiquitousunanimousunicornunificationuniformuniformeduniformityunifyingunilateralunilateralistunionuniqueunisexunituniteduniversaluniverseuniversityuraniumurinalurinaryurineusableusageuseusedusefuluselessuserusualusuallyusurperutensiluterusutilitarianutilityutopian

You use an in front of an abbreviation when the letters are pronounced separately and the first letter begins with a vowel sound.

Before she became an MP, she was a social worker.He drives an SUV.3. 'a' meaning 'one'

A and an are used to mean 'one' in front of some numbers and units of measurement.

a

Past participle: aed
Gerund: aing

Imperative	aa

Present	I ayou ahe/she/it aswe ayou athey a

Preterite	I aedyou aedhe/she/it aedwe aedyou aedthey aed

Present Continuous	I am aingyou are ainghe/she/it is aingwe are aingyou are aingthey are aing

Present Perfect	I have aedyou have aedhe/she/it has aedwe have aedyou have aedthey have aed

Past Continuous	I was aingyou were ainghe/she/it was aingwe were aingyou were aingthey were aing

Past Perfect	I had aedyou had aedhe/she/it had aedwe had aedyou had aedthey had aed

Future	I will ayou will ahe/she/it will awe will ayou will athey will a

Future Perfect	I will have aedyou will have aedhe/she/it will have aedwe will have aedyou will have aedthey will have aed

Future Continuous	I will be aingyou will be ainghe/she/it will be aingwe will be aingyou will be aingthey will be aing

Present Perfect Continuous	I have been aingyou have been ainghe/she/it has been aingwe have been aingyou have been aingthey have been aing

Future Perfect Continuous	I will have been aingyou will have been ainghe/she/it will have been aingwe will have been aingyou will have been aingthey will have been aing

Past Perfect Continuous	I had been aingyou had been ainghe/she/it had been aingwe had been aingyou had been aingthey had been aing

Conditional	I would ayou would ahe/she/it would awe would ayou would athey would a

Past Conditional	I would have aedyou would have aedhe/she/it would have aedwe would have aedyou would have aedthey would have aed

A

A member of the highest grouping into which society is divided by occupation, typically a senior manager, administrator, or professional.

Thesaurus

Noun

1.A - a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiationangstrom, angstrom unitmetric linear unit - a linear unit of distance in metric termsmicromicron, picometer, picometre - a metric unit of length equal to one trillionth of a metermicromillimeter, micromillimetre, millimicron, nanometer, nanometre, nm - a metric unit of length equal to one billionth of a meter

A - any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyesantiophthalmic factor, axerophthol, vitamin Afat-soluble vitamin - any vitamin that is soluble in fatsretinol, vitamin A1 - an unsaturated alcohol that occurs in marine fish-liver oils and is synthesized biologically from carotenedehydroretinol, vitamin A2 - a viscous alcohol that is less active in mammals than is vitamin A1

A - one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)deoxyadenosine monophosphatenucleotide, base - a phosphoric ester of a nucleoside; the basic structural unit of nucleic acids (DNA or RNA)

A - (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNAadeninebiochemistry - the organic chemistry of compounds and processes occurring in organisms; the effort to understand biology within the context of chemistrypurine - any of several bases that are derivatives of purinedeoxyribonucleic acid, desoxyribonucleic acid, DNA - (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information; "DNA is the king of molecules"ribonucleic acid, RNA - (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell; "ribonucleic acid is the genetic material of some viruses"

A - the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps"amp, amperecurrent unit - a measure of the amount of electric charge flowing past a circuit point at a specific timemilliampere, mA - one thousandth of an ampereabamp, abampere - a unit of current equal to 10 amperes

a - the 1st letter of the Roman alphabetLatin alphabet, Roman alphabet - the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europealphabetic character, letter of the alphabet, letter - the conventional characters of the alphabet used to represent speech; "his grandmother taught him his letters"

A - the blood group whose red cells carry the A antigengroup A, type Ablood group, blood type - human blood cells (usually just the red blood cells) that have the same antigens

Translations

A

(ei) noun one of the notes in the musical scale. 音阶的音符之一A flat (ˌei ˈflat) noun (music) a note that is a semitone lower than A. （音乐）低于A音的半音 A sharp (ˌei ˈʃaːp) noun (music) a note that is a semitone higher than A. （音乐）高于A音的半音

a,

an

(ə(n)) indef. article (a is used before words beginning with a consonant eg a boy, or consonant sound eg a union; an is used before words beginning with a vowel eg an owl, or vowel sound eg an honour.) 1. one. There is a boy in the garden. 一（个） 2. any; every. An owl can see in the dark.任何一个或每一个3. for each; per. We earn $6 an hour.每个

a before hotel, ~historian.
an before heir, ~honest, ~honour, ~hour.

a

→

Just a moment, please

I'm on a diet

A month from now (US)
In a month's time (UK)

A week from today (US)
In a week's time (UK)

A

Acronym	Definition
A➣Area
A➣Blood Type
A➣Activity
A➣Approved
A➣Accommodation
A➣Battery Size
A➣Atomic (as in A-bomb)
A➣Ampere
A➣Accusative
A➣USDA Grade for Dairy Products and Eggs
A➣About
A➣To (Spanish, or from Latin ad)
A➣Adult
A➣Are (unit of area)
A➣Amateur
A➣Year
A➣Ass
A➣Account
A➣Action
A➣Advanced
A➣Individual (IRB)
A➣Advanced Digital Audio (filename extension)
A➣First in Series (chemistry)
A➣Away (Sports)
A➣Author
A➣Association
A➣Ask
A➣Active
A➣Excellent (scholastic grade)
A➣American Bank Note Company (numismatic/philatelic)
A➣Anna
A➣Answer
A➣Article
A➣Accept
A➣Availability
A➣Austria (international car index mark)
A➣Agency
A➣Administration
A➣Add(ed) (action code)
A➣Annual
A➣Analysis
A➣GMT + 1 hour
A➣Advanced Levels (highest level of academic boards, UK)
A➣Assist (Sports)
A➣Attack (US military aircraft designation, as in A-10)
A➣Army (in combinations only)
A➣Apple
A➣Agreed To (that an amendment or other matter was approved; US House)
A➣Army
A➣Anonymous
A➣Mass Number (physics)
A➣Australian
A➣Academy
A➣Absolute (degrees Kelvin)
A➣Analysis and Assessment (LANL)
A➣Alpha
A➣Ace
A➣Automobile
A➣Assembly Source Code (Macintosh filename extension)
A➣Afternoon
A➣Ace (used on playing cards)
A➣Alto
A➣Anno
A➣Anchor (HTML)
A➣Analog
A➣Aircraft
A➣Analog Signal
A➣Adjacent (to a carboxyl group; chemistry)
A➣Aqua
A➣Arc
A➣Atomic Mass
A➣Aggressive Personality Type
A➣Annually
A➣Anterior
A➣Acre
A➣Arctic
A➣Ante (Latin: Before)
A➣Aft
A➣Applet
A➣Airplane
A➣Specific Optical Rotation
A➣Algemeen
A➣Arse
A➣Aerial
A➣Absent
A➣And
A➣Newfoundland/Labrador (Canada Post designation)
A➣Avance (French: fast)
A➣Allegro (game programming library)
A➣Alpha Particle
A➣Auditor
A➣Atto-
A➣Acceleration
A➣Adultery (as in the Scarlet Letter)
A➣Acronym
A➣Abbreviation
A➣Artillery
A➣Artery
A➣First Substrate
A➣Amphibian (aircraft type)
A➣Arterial Road (used with road numbers)
A➣At or Above (constrained altitude)
A➣Arterial blood
A➣Specific Absorption Coefficient
A➣Airbus
A➣Amplitude
A➣Adjective
A➣Argon
A➣Total Acidity
A➣Asymmetric
A➣Retinol (vitamin)
A➣Accumulator
A➣Autostrada (Italian notation for highways)
A➣Airman
A➣Adjutant
A➣Anode
A➣Smooth, Paintable (American Plywood Association Veneer Grades)
A➣Degree of Dissociation
A➣Helmholtz Energy
A➣Auris (Latin: ear)
A➣Alveolar Gas
A➣Alanine
A➣Adenosine
A➣Animaniacs
A➣Aliphatic Chain (chemistry)
A➣Angstrom (should be written with Å; unit of length)
A➣Adenine (one of four DNA building blocks)
A➣Avianca Airlines (philatelic airmail overprint)
A➣Absorbance
A➣Agouti
A➣Absorptance
A➣Alwaya (dinnerware trademark)
A➣Adenylic Acid
A➣Amendment of Application (insurance)
A➣Nucleon Number (physics)
A➣Aromatic Substituent (chemistry)
A➣Agilent Technologies Incorporated (stock symbol)
A➣Assisted Citizen (Alabama Public Safety Radio Code)
A➣Stock and Bond Rating
A➣Federal Reserve Bank of Boston, Massachusetts (designates original spot of circulation of a bill)
A➣Applanation Tension (pressure in the eye)
A➣Bunsen Solubility Coefficient
A➣Angle of Asymmetry (NIOSH)
A➣Assay and Accountability (LANL)
A➣Autotuned Navaid (aviation navigational aid)
A➣Aktopia
A➣Highest Level of Division I College Athletics (United States)
A➣Accelerating Contactor or Relay
A➣Lowest Full-Season Level (minor league baseball)
A➣Undenominated US Stamp (15 cent, issued 22 May 78)
A➣Air Force training category (15 days active duty training per year)

A

a-

A

a 1

a 2

a 3

a 4

a 5

a

A

a

a

a

a

A

Å

A, a

a1

a2

a3

a4

Å

A

A

a

A-

a-1

a-2

a-3

a-4

a-5

a-6

-a1

-a2

-a4

A.

a.

A

a

a

A

A

a,

an

a

A

A

A

ā

α

A

A

a

a

A

a

A

A

a

°A

V̊A

A

A

a

a

A

Å

A

Ā

A

A

A

A

A

a

A

A

Synonyms for A

nouna metric unit of length equal to one ten billionth of a meter (or 0.0001 micron)

Synonyms

a¹

a²

a³

a⁴

a⁵

a¹

a²

a³

a⁴

a-¹

a-²

a-³

a-⁴

a-⁵

a-⁶

-a¹

-a²

-a⁴

V̊_A