WordReference Random House Unabridged Dictionary of American English © 2026
mi•cro•ev•o•lu•tion
(mī′krō ev′ə lo̅o̅′shən or, esp. Brit., -ē′və-),USA pronunciation n. [Biol.]
mi′cro•ev′o•lu′tion•ar′y, adj.
- Biologyevolutionary change involving the gradual accumulation of mutations leading to new varieties within a species.
- Biologyminor evolutionary change observed over a short period of time.
- micro- + evolution 1935–40