取代基

substituent (chemistry)

to take / to get / to choose / to fetch

(bound form) base; foundation / (bound form) radical (chemistry) / (bound form) gay (loanword from English into Cantonese, Jyutping: gei1, followed by orthographic borrowing from Cantonese)

to substitute / to act on behalf of others / to replace / generation / dynasty / age / period / (historical) era / (geological) eon

to replace / to supersede / to supplant / (chemistry) substitution