/di sim'euh lay"sheuhn/ , n.
1. the act of making or becoming unlike.
2. Phonet. the process by which a speech sound becomes different from or less like a neighboring sound, as pilgrim /pil"grim/ from Latin peregrinus /perdd'e grddee"noos/ , and purple /perr"peuhl/ from Old English purpure /poordd"poo rdde/ , or disappears entirely because of a like sound in another syllable, as in the pronunciation /guv"euh neuhr/ for governor. Cf. assimilation (def. 5).
3. Biol. catabolism.
[ 1820-30; DIS- 1 + (AS)SIMILATION ]