prime¹ / prīm/ • adj. 1. of first importance; main: her prime concern is the well-being of the patient. ∎  from which another thing may derive or proceed: Diogenes' conclusion that air is the prime matter.2. of the best possible quality; excellent: a prime site in the center of Indianapolis prime cuts of meat. ∎  having all the expected or typical characteristics of something: the novel is a prime example of the genre. ∎  most suitable or likely: it's the prime contender for best comedy of the year.3. Math. (of a number) evenly divisible only by itself and one (e.g., 2, 3, 5, 7, 11). ∎  (of two or more numbers in relation to each other) having no common factor but one.• n. 1. [in sing.] a state or time of greatest strength, vigor, or success in a person's life: you're in the prime of life he wasn't elderly, but clearly past his prime. ∎ archaic the beginning or first period of something: the prime of the world.2. Christian Church a service forming part of the Divine Office, traditionally said (or chanted) at the first hour of the day (i.e., 6 a.m.), but now little used. ∎ archaic this time of day.3. a prime number.4. Printing a symbol (′) written after a letter or symbol as a distinguishing mark or after a figure as a symbol for minutes or feet.5. Fencing the first of eight standard parrying positions.6. short for prime rate.DERIVATIVES: prime·ness n.prime² • v. [tr.] 1. make (something) ready for use or action, in particular: ∎  prepare (a firearm or explosive device) for firing or detonation. ∎  cover (wood, canvas, or metal) with a preparatory coat of paint in order to prevent the absorption of subsequent layers of paint. ∎  pour or spray liquid into (a pump) before starting in order to seal the moving parts and facilitate its operation. ∎  inject extra fuel into (the cylinder or carburetor of an internal combustion engine) in order to facilitate starting. ∎  [intr.] (of a steam engine or its boiler) mix water with the steam being passed into the cylinder. ∎  Biochem. serve as a starting material for (a polymerization process).2. prepare (someone) for a situation or task, typically by supplying them with relevant information: [tr.] the sentries had been primed to admit him without challenge. PHRASES: prime the pump stimulate or support the growth or success of something by supplying it with money: capital from overseas that helps prime the U.S. economic pump.

prime1 in the Christian Church, a service forming part of the Divine Office of the Western Church, traditionally said (or chanted) at the first hour of the day (i.e. 6 a.m.), but now little used. In monastic rules such as the Regula Magistri and the Rule of St Benedict (both dating from the 6th century), prima is the first of the Little Hours (the others are tierce, sext, and none). It is believed to have been introduced by Cassian at his monastery in Bethlehem in the late 4th century. Prime is not included in the reordered breviary of the Divine Office issued by Pope Paul VI in 1971.

Recorded in Old English (in the form prīm), the word comes from Latin prima (hora) ‘first (hour)’.

prime2 † first in order of time XIV; (arith.) having no integral factors but itself and one XVI; of first rank, importance, or quality XVII; p. minister PREMIER XVII. (O)F. — L. prīmus first, f. *prī́-, rel. to præ PRE-, prṓ PRO-1, PRO-2.
Hence prime sb. prime number XVI.

Prime ★★½ 2005 (PG-13)

Streep plays Lisa, an interfering Jewish mama, fretting over her handsome 23yearold son, David (Greenberg). Lisa's a shrink; one of her needier patients is newly divorced Rafi (Thurman) who's beautiful but insecure. Rafi is happy but fretful over a new romance with a muchyounger guy, who, of course, turns out to be Lisa's son David. Lisa is the first to realize this and suffers agonies of embarrassment as Rafi enthusiastically describes her rejuvenated sex life. Lots more embarrassment is to come for all concerned. Harmless comedic fluff. 105m/C DVD . US Meryl Streep, Uma Thurman, Bryan Greenberg, Jon Abrahams, Zak Orth, Annie Parisse; D: Ben Younger; W: Ben Younger; C: William Rexer; M: Ryan Shore.

prime3 of first importance.
prime minister the head of an elected government; the principal minister of a sovereign or state. In Britain Robert Walpole is regarded as having been the first Prime Minister in the modern sense. By the middle of the 19th century the term had become common in informal use, and in 1905 it was formally recognized.
prime number a number that is divisible only by itself and unity (e.g. 2, 3, 5, 7, 11). Formerly also, the golden number.