tác nhân

== Vietnamese == === Etymology === Sino-Vietnamese word from 作 (“to do”) and 因 (“cause”). === Pronunciation === (Hà Nội) IPA(key): [taːk̚˧˦ ɲən˧˧] (Huế) IPA(key): [taːk̚˦˧˥ ɲəŋ˧˧] (Saigon) IPA(key): [taːk̚˦˥ ɲəŋ˧˧] === Noun === tác nhân (biology, chemistry) agent