- a combining form meaning “outer,” “outside,” “external,” used in the formation of compound words: ectoderm.
- indicating outer, outside, externalectoplasm
word-forming element generally meaning “outside, external,” before vowels ect-, comb. form of Greek ektos “outside” (adv.), used to form scientific compounds in Greek; related to Greek ek, ex “out,” from PIE *eghs- (see ex-).
- Outer; external:ectoparasite.