Etymology: Middle English corps , originally merely a variant spelling of the earlier Middle English cors (see corse n.), < Old French (11–14th cent.) cors = Provençal cors < Latin corpus body. In the 14th cent. the spelling of Old French cors was perverted after Latin to corps , and this fashion came also into English, where corps is found side by side with cors , and became gradually (by 1500) the prevalent, and at length the ordinary form, while at the same time cors , from 16th cent. spelt corse n., has never become obsolete. In French the p is a mere bad spelling, which has never affected the pronunciation. In English also, at first, the p was mute, corps being only a fancy spelling of cors ; but apparently by the end of the 15th cent. (in some parts of the country, or with some speakers) the p began to be pronounced, and this became at length the ordinary practice; though even at the present day some who write corpse pronounce corse , at least in reading. The spelling with final e , corpse (perhaps taken from the modern plural corpses ) was only a rare and casual variation before the 19th cent., in which it has become the accepted form in the surviving sense 2, which is thus differentiated < corps n.¹, used with French pronunciation in the military sense. In French cors, corps the plural is the same as the singular; in English also the ordinary plural down to 1750 was corps, though corpses is occasional from 16th cent. In the 17th cent. corps meaning a single dead body was often construed as a plural = ‘remains’, as is still the case dialectally; in Scots, corps plural gave rise to a truncated singular corp before 1500. Comparing the history of French cors, corps, and that of English cors, corps, corpse, we see that while modern French /kɔr/ has in pronunciation lost the final s, English has not only retained it, but pronounces the p, and adds a final e mute, which is neither etymological nor phonetic, but serves to distinguish the word from the special sense spelt corps and pronounced /kɔə(r)/.

Etymology: < corpse n.