"signal given at break of day to soldiers and sentries" (originally by drum or bugle), 1640s, from French réveillez-vous "awaken!" imperative plural of réveiller "to awaken, to wake up," from re- "again" (see re-) + Middle French eveiller "to rouse," from Vulgar Latin *exvigilare, from Latin ex- "out" (see ex-) + vigilare "be awake, keep watch" (from PIE root *weg- "to be strong, be lively").
1630s, "to turn aside or ward off" the blow of a weapon (transitive), from French parez! (a word which would have been heard often in fencing lessons), imperative of parer "ward off," from Italian parare "to ward or defend (a blow)" (see para- (2)). Related: Parried; parrying. Non-fencing use is from 1718. The noun, "an act of warding off or turning aside," is by 1705, from the verb.
1719, alteration of salva (1590s) "simultaneous discharge of guns," from Italian salva "salute, volley" (French salve, 16c., is from Italian), from Latin salve "hail!," literally "be in good health!," the usual Roman greeting, regarded as imperative of salvere "to be in good health," but properly vocative of salvus "healthy" (from PIE root *sol- "whole, well-kept"). The notion is of important visitors greeted with a volley of gunfire into the air; applied afterward to any concentrated fire from guns.
late 14c., "Psalm cxxxi in the Canon of the Mass" (which begins with the Latin word Memento and in which the dead are commemorated), from Latin memento "remember," second person singular imperative of meminisse "to remember, recollect, think of, bear in mind," a reduplicated form, related to mens "mind," from PIE root *men- (1) "to think." Meaning "a hint or suggestion to awaken memory, a reminder, an object serving as a warning" is from 1580s; sense of "keepsake" is recorded by 1768.
in law, "a writ commanding something to be done or requiring a reason for its non-performance," c. 1500 (in Magna Carta in Anglo-Latin), from Latin praecipe, imperative of praecipere "to admonish, enjoin, take or seize beforehand," from the opening words of such a writ, praecipe quod reddat "enjoin (him) that he render." From prae (adv.) "before (see prae-) + -cipere, combining form of capere "to take," from PIE root *kap- "to grasp."
1540s, "of a dominating character," from Latin imperiosus "commanding, mighty, powerful," from imperium "empire, command" (see empire). Formerly also emperious. Meaning "imperial" is from 1580s. Related: Imperiously; imperiousness.
Imperious applies to the spirit or manner of the person ruling or giving a command, and of rule in general; imperative, to the nature of a command. An imperious person is determined to have his will obeyed; imperious rule is characterized by the haughty, overbearing, and determined nature of the ruler. [Century Dictionary]
c. 1200, dirige (the contracted form is from c. 1400), "that part of the Office for the Dead beginning with the antiphon for the first psalm of the first nocturn of matins," from Latin dirige "direct!" imperative of dirigere "to direct" (see direct (v.)). The antiphon begins, Dirige, Domine, Deus meus, in conspectu tuo viam meam ("Direct, O Lord, my God, my way in thy sight"), from Psalms v.9.
Hence, broadly, "the funeral service as sung." Transferred sense of "any funeral song or hymn, a song or tune expressing grief" is from c. 1500.
1580s, "medical prescription, a formula for the composing of a remedy written by a physician," from French récipé (15c.), from Latin recipe "take!" (this or that ingredient), second person imperative singular of recipere "to hold, contain" (see receive). It was the word written by physicians at the head of prescriptions. Figurative meaning "a prescribed formula" is from 1640s. Meaning "instructions for preparing a particular food" is recorded by 1716. The older sense in English survives chiefly in the pharmacist's abbreviation Rx. Compare receipt.