prime (or first) meridian

The meridian from which longitudes are measured east or west, specif that through Greenwich

prime¹ /prīm/

1. First in order of time, rank or importance
2. Primary
3. Chief
4. Main
5. Of the highest quality
6. Supremely typical
7. (of broadcasting time) commanding the highest audience figures
8. Original
9. In sexual excitement (Shakespeare)
10. (of a number other than one) divisible by no whole number except unity and itself (mathematics)
11. (of two or more numbers) relatively prime (see below) (with to; mathematics)

1. One of the hours of the Divine Office, orig held at the first hour of the day (6am) (RC)
2. The time from the beginning of the artificial day to terce
3. The beginning
4. The spring
5. The world's youth
6. The new moon, or its first appearance (obsolete)
7. The best part
8. The height of perfection
9. Full health and strength
10. A prime number
11. A first subdivision or symbol marking it (ˈ) (mathematics, etc)
12. A fundamental tone
13. An old card game, probably the same as primero
14. The first guard against sword thrusts, also the first and simplest thrust (fencing)

primeˈly adverb

primeˈness noun

prīˈmy adjective (Shakespeare)

In one's prime, blooming

prime cost see under cost¹

prime meridian noun

A meridian chosen to represent 0º, esp that passing through Greenwich, from which other lines of longitude are calculated

prime minister noun

1. The head of a parliamentary government
2. The chief minister of state

prime mover noun

1. In medieval astronomy, the primum mobile
2. A natural source of energy
3. A machine that transforms energy from such a source into motive power
4. The main cause or instigator of an action, project, etc

prime number noun

A number, other than one, divisible only by itself or unity

prime rate or prime lending rate noun

The lowest rate of interest charged by a bank at any given time, usu available only to large concerns with high credit ratings, forming the base figure on which other rates are calculated

prime time noun (radio and TV)

The peak period for viewing and listening during the day, having the highest rates

primeˈ-time adjective

prime vertical noun

A great celestial circle passing through the east and west points of the horizon, and cutting the meridian at right angles at the zenith

prime of life

The period of one's life following youth, during which one is at one's most active, productive and successful

relatively prime (mathematics)

Having no common integral factor but unity