base 1 
(bās)
(bās)n.
1. The lowest or bottom part: the base of a cliff; the base of a lamp.
2. Biology
a. The part of a plant or animal organ that is nearest to its point of attachment.
b. The point of attachment of such an organ.
3.
a. A supporting part or layer; a foundation: a skyscraper built on a base of solid rock.
b. A basic or underlying element; infrastructure: the nation's industrial base.
4. The fundamental principle or underlying concept of a system or theory; a basis.
5. A fundamental ingredient; a chief constituent: a paint with an oil base.
6. The fact, observation, or premise from which a reasoning process is begun.
7.
a. Games A starting point, safety area, or goal.
b. Baseball Any one of the four corners of an infield, marked by a bag or plate, that must be touched by a runner before a run can be scored.
8.
a. A center of organization, supply, or activity; a headquarters.
b. The portion of a social organization, especially a political party, consisting of the most dedicated or motivated members.
9.
a. A fortified center of operations.
b. A supply center for a large force of military personnel.
10. A facial cosmetic used to even out the complexion or provide a surface for other makeup; a foundation.
11. Architecture The lowest part of a structure, such as a wall, considered as a separate unit: the base of a column.
12. Heraldry The lower part of a shield.
13. Linguistics A morpheme or morphemes regarded as a form to which affixes or other bases may be added.
14. Mathematics
a. The side or face of a geometric figure to which an altitude is or is thought to be drawn.
b. The number that is raised to various powers to generate the principal counting units of a number system. The base of the decimal system, for example, is 10.
c. The number raised to the logarithm of a designated number in order to produce that designated number; the number at which a chosen logarithmic scale has the value 1.
15. A line used as a reference for measurement or computations.
16. Chemistry
a. Any of a class of compounds whose aqueous solutions are characterized by a bitter taste, a slippery feel, the ability to turn litmus blue, and the ability to react with acids to form salts.
b. A substance that yields hydroxide ions when dissolved in water.
c. A substance that can act as a proton acceptor.
d. A substance that can donate a pair of electrons to form a covalent bond.
17. Electronics
a. The region in a transistor between the emitter and the collector.
b. The electrode attached to this region.
18. One of the nitrogen-containing purines (adenine and guanine) or pyrimidines (cytosine, thymine, and uracil) that occurs attached to the sugar component of DNA or RNA.
adj.
1. Forming or serving as a base: a base layer of soil.
2. Situated at or near the base or bottom: a base camp for the mountain climbers.
3. Chemistry Of, relating to, or containing a base.
tr.v. based, bas·ing, bas·es
Idiom: 1. To form or provide a base for: based the new company in Portland.
2. To find a basis for; establish: based her conclusions on the report; a film based on a best-selling novel.
3. To assign to a base; station: troops based in the Middle East.
off base
Badly mistaken.
[Middle English, from Old French, from Latin basis, from Greek; see gwā- in the Appendix of Indo-European roots.]
Synonyms: base1, basis, foundation, ground1, groundwork
These nouns all pertain to what underlies and supports. Base is used broadly in both literal and figurative contexts: the wide base of the pyramid; a party seeking to expand its power base.
Basis is used in a nonphysical sense: "Healthy scepticism is the basis of all accurate observation" (Arthur Conan Doyle).
Foundation often stresses firmness of support for something of relative magnitude: "Our flagrant disregard for the law attacks the foundation of this society" (Peter D. Relic).
Ground is used figuratively, especially in the plural, to mean a justifiable reason: grounds for divorce.
Groundwork usually has the sense of a necessary preliminary: "It [the Universal Declaration of Human Rights] has laid the groundwork for the world's war crimes tribunals" (Hillary Rodham Clinton).
These nouns all pertain to what underlies and supports. Base is used broadly in both literal and figurative contexts: the wide base of the pyramid; a party seeking to expand its power base.
Basis is used in a nonphysical sense: "Healthy scepticism is the basis of all accurate observation" (Arthur Conan Doyle).
Foundation often stresses firmness of support for something of relative magnitude: "Our flagrant disregard for the law attacks the foundation of this society" (Peter D. Relic).
Ground is used figuratively, especially in the plural, to mean a justifiable reason: grounds for divorce.
Groundwork usually has the sense of a necessary preliminary: "It [the Universal Declaration of Human Rights] has laid the groundwork for the world's war crimes tribunals" (Hillary Rodham Clinton).