"the same (as above)," used to avoid repetition in writing, Latin, literally "the same," from id "it, that one," from PIE pronominal stem *i- (see yon) + demonstrative suffix -dem.
Entries linking to idem
yon adj., pron.
Old English geon "that (over there)," from Proto-Germanic *jaino- (source also of Old Frisian jen, Old Norse enn, Old High German ener, Middle Dutch ghens, German jener, Gothic jains "that, you"), from PIE pronominal stem *i- (source also of Sanskrit ena-, third person pronoun, anena "that;" Latin idem "the same," id "it, that one;" Old Church Slavonic onu "he;" Lithuanian ans "he"). As an adverb from late 15c., a shortening of yonder.
idempotent n.
in algebra, quantity which multiplied by itself gives itself, 1870, from Latin idem "the same, identical with" (see idem) + potentem "powerful" (see potent).
yon (adj., pron.)idempotent (n.)identical (adj.)identity (n.)semper idem