The first hour of daylight; the first canonical hour. • The religious service appointed to this hour. • The early morning generally. • The earliest stage of something. • The most active, thriving, or successful stage or period. • The chief or best individual or part. • Something which is first in importance or rank: a prime defense company, mortgage lender, etc. • The first note or tone of a musical scale. • The first defensive position, with the sword hand held at head height, and the tip of the sword at head height. • A prime element of a mathematical structure, particularly a prime number. • A four-card hand containing one card of each suit in the game of primero; the opposite of a flush in poker. • A series of consecutive blocks. A prime of six prevents the opponent's pieces from passing. • The symbol ′ used to indicate feet, minutes, derivation and other measures and mathematical operations. • Any number expressing the combining weight or equivalent of any particular element; so called because these numbers were respectively reduced to their lowest relative terms on the fixed standard of hydrogen as 1. • An inch, as composed of twelve seconds in the duodecimal system. • The priming in a flintlock. • Contraction of prime lens, a film lens. • A feather, from the wing of the cock ostrich, that is of the palest possible shade. • A stimulus which causes priming.