Prime1, a.
a. [Lat. primus, first; It. & Sp. primo. Cf. PRIM.]
Sense 1. First in order of time; original; primitive; primary. “Better to clear prime forests.” Tennyson.
She was not the prime cause, but I myself. Shak.
☞ In this sense, the word is nearly superseded by primitive, except in the phrase prime cost.
Sense 2. First in rank, degree, dignity, or importance; as, prime minister.
Sense 3. First in excellence; of highest quality; as, prime wheat; cloth of a prime quality.
Sense 4. Early; blooming.
His starry helm, unbuckled, showed him prime In manhood, where youth ended. Milton.
Sense 5. Lecherous; lustful; lewd. [Obs.] Shak.
Prime figure (Geom.), a figure which can not be divided into any other figure more simple than itself, as a triangle, a pyramid, &c.—Prime meridian (Astron.), the meridian from which longitude is reckoned, as the meridian of Greenwich or Washington.—Prime minister, the responsible head of a ministry or executive government;—applied particularly to that of England.—Prime mover. (Mech.) (a.) A natural force applied by man to the production of power; especially, muscular force, the weight and motion of fluids, as water and air, heat obtained by chemical combination, and applied to produce changes in the volume and pressure of steam, air, or other fluids, and electricity, obtained by chemical action, and applied to produce alternation of magnetic force. (b.) An engine, or piece of mechanism, the object of which is to receive and modify force and motion as supplied by some natural source, and apply them to drive other machines, as a water-wheel, a water-pressure engine, a steam-engine, a heat or hot-air engine, &c.—Prime number (Arith.), a number which is divisible only by itself or unity, as 5, 7, 11.—Prime vertical (Astron.), the vertical circle which passes through the east and west points of the horizon.—Prime vertical dial, a dial projected on the plane of the prime vertical; a north and south dial.—Prime vertical transit instrument, a transit instrument, the telescope of which revolves in the plane of the prime vertical, used for observing the transit of stars over this circle. The telescope is usually fixed to the extremity of the axis, to allow the latter to carry the riding level in all positions of the instrument.