1550s, "engagement to marry," a variant of ensurance "an assurance, pledge, guarantee," from Old French enseurance "assurance," from ensurer, from en- "make" (see en- (1)) + sur "safe, secure, undoubted" (see sure (adj.)).
Commercial sense of "security against loss or death in exchange for payment" is from 1650s. Assurance was the older word for this specific sense (late 16c.). Compare insure.
late 14c., "to give in charge, entrust," from Latin committere "to unite, connect, combine; to bring together," from com "with, together" (see com-) + mittere "to release, let go; send, throw" (see mission).
The evolution of the modern range of meanings in English is not entirely clear. Sense of "to perpetrate (a crime), do, perform (especially something reprehensible)" was ancient in Latin; in English it is attested from mid-15c. Meaning "consign (someone) to custody (of prison, a mental institution, etc.) by official warrant" is from early 15c.
From 1530s as "trust (oneself) completely to;" from 1770 as "put or bring into danger by an irrevocable preliminary act." The intransitive use (in place of commit oneself) first recorded 1982, probably influenced by existentialism use (1948) of commitment to translate Sartre's engagement "emotional and moral engagement."
"fight or hostile engagement between opposing forces," c. 1300, from Old French bataille "battle, single combat," also "inner turmoil, harsh circumstances; army, body of soldiers," from Late Latin battualia "exercise of soldiers and gladiators in fighting and fencing," from Latin battuere "to beat, to strike" (see batter (v.)).
Battle-cry is from 1812; battle-flagfrom 1840; battle-scarred is from 1848. Phrase battle royal "fight involving several combatants" is from 1670s.
"solemn promise," c. 1300, from Anglo-French and Old French voe (Modern French vœu), from Latin votum "a promise to a god, solemn pledge, dedication; that which is promised; a wish, desire, longing, prayer," noun use of neuter of votus, past participle of vovere "to promise solemnly, pledge, dedicate, vow," from PIE root *wegwh- "to speak solemnly, vow, preach" (source also of Sanskrit vaghat- "one who offers a sacrifice;" Greek eukhe "vow, wish," eukhomai "I pray"). The meaning "solemn engagement to devote oneself to a religious order or life" is from c. 1400; earlier "to bind oneself" to chastity (early 14c.).
late 14c., mesche, "open space in a net or netting," probably from late Old English max "net," earlier mæscre, from Proto-Germanic *mask- (source also of Old Norse möskvi, Danish maske, Swedish maska, Old Saxon masca, Middle Dutch maessce, Dutch maas "mesh," Old High German masca, German Masche "mesh"), from PIE *mezg- "to knit, plait, twist" (source also of Lithuanian mezgu, megzti "to knit," mazgas "knot"). In machinery, "the engagement of the teeth in gearing" (by 1875). Mesh-work in netting is attested by 1785.
mid-14c., plegge, "surety, bail," from Old French plege (Modern French pleige) "hostage, security, bail," also Anglo-Latin plegium, both probably from Frankish *plegan "to guarantee," from *pleg-, a West Germanic root meaning "have responsibility for" (source also of Old Saxon plegan "vouch for," Middle Dutch plien "to answer for, guarantee," Old High German pflegan "to care for, be accustomed to," Old English pleon "to risk the loss of, expose to danger"), from PIE root *dlegh- "to engage oneself, be or become fixed" [Watkins].
From late 14c. as "person who goes surety or gives bail for another;" late 15c. (Caxton) as "personal property given as surety for a debt or engagement. By 1520s as "a token or sign of favor, agreement, etc.
Meaning "allegiance vow attested by drinking with another" is from 1630s. Sense of "solemn promise, one's word given or considered as security for the performance (or refraining from) an act" is recorded by 1814, though this notion is from 16c. in the verb. Weekley notes the "curious contradiction" in pledge (v.) "to toast with a drink" (1540s) and pledge (n.) "the vow to abstain from drinking" (1833). Meaning "student who has agreed to join a fraternity or sorority" dates from 1901.
late Old English, in Christian use, "an outward and visible sign of inward and spiritual grace," especially "a sacrament of the Church, one of the religious ceremonies enjoined by Christ or the Church," and later specifically "the sacrament of the Eucharist" (c. 1300), from Old French sacrament "consecration; mystery" (12c., Modern French sacrement) and directly from Latin sacramentum, "a solemn oath" (source also of Spanish sacramento, German Sakrament, etc.), from sacrare "to consecrate" (see sacred).
A Church Latin loan-translation of Greek mysterion (see mystery). The Latin word sacramentum in its secular aspect was used of any engagement or ceremony that binds or imposes obligation, specifically "oath of obedience and fidelity taken by Roman soldiers on enlistment; sum which two parties to a suit first deposit," hence also, "a cause, a civil suit," thus either "a result of consecration" or "a means of consecration." By 3c. it was used in Church Latin for "a mystery, a sacrament, something to be kept sacred; the gospel revelation; a Church sacrament." In theology, particularly, "a solemn religious ceremony enjoined by Christ, or by the church, for the spiritual benefit of the church or of individual Christians, by which their special relation to him is created or recognized or their obligations to him are renewed and ratified."
The meaning "arcane knowledge; a secret; a mystery; a divine mystery" in English is from late 14c. (Wycliffe); from mid-14c. as "a solemn oath, pledge, covenant; a ceremony accompanying the taking of an oath or the making of a pledge." The seven sacraments in the West were baptism, penance, confirmation, holy orders, the Eucharist, matrimony, and anointing of the sick (extreme unction); the Reformation loosened the sense in England.