1620s, "military stores and provisions," from French soldiers' faulty separation of French la munition, as if *l'amunition; from Latin munitionem (nominative munitio) "a fortifying" (see munition).
The mistake in the word perhaps was by influence of French a(d)monition "warning." The error was corrected in French (Modern French munition), but retained in English, with spelling conformed to words in Latin. At first meaning all military supplies in general, in modern use only material used in the discharge of firearms and ordnance.
Old English cest "box, coffer, casket," usually large and with a hinged lid, from Proto-Germanic *kista (source also of Old Norse and Old High German kista, Old Frisian, Middle Dutch, German kiste, Dutch kist), an early borrowing from Latin cista "chest, box," from Greek kistē "a box, basket," from PIE *kista "woven container" (Beekes compares Middle Irish cess "basket, causeway of wickerwork, bee-hive," Old Welsh cest).
The meaning of the English word was extended to "thorax, trunk of the body from the neck to the diaphragm" c. 1400, replacing breast (n.) in that sense, on the metaphor of the ribs as a "box" for the heart. Meaning "place where public money is kept (common chest, mid-15c.) was extended to "public funds" (1580s). Chest of drawers is from 1670s.
"ammunition wagon; wooden chest for bombs, gunpowder, etc.," 1704, from French caisson "ammunition wagon," originally "large box" (16c.), from Italian cassone, augmentative form of cassa "a chest," from Latin capsa "a box" (see case (n.2)).
"chest of the body," late 14c., from Latin thorax "the breast, chest; breastplate," from Greek thōrax (genitive thōrakos) "breastplate, chest," of unknown origin.
1570s, "of or pertaining to the breast or chest," from Latin pectoralis "of the breast," from pectus (genitive pectoris) "breast, chest," a word of unknown origin. De Vaan considers Old Irish ucht "breast, chest" as "a likely cognate, if it reflects earler *pektu-." Pectoral muscle is attested from 1610s.
1804, in British archaeology, "sepulchral chest or chamber;" 1847, in Greek history, "small receptacle for sacred utensils in a procession;" in the second sense from Latin cista "wickerwork basket, box," from Greek kistē "box, chest" (see chest); in the first sense from Welsh cist in cist faen "stone coffin," the first element of which is from the Latin word.