"(Of a lake or other body of water) rich in nutrients and so supporting a dense plant population, the decomposition of which kills animal life by depriving it of oxygen", Early 18th century (denoting a medicine promoting good nutrition): from Greek eutrophia, from eu 'well' + trephein 'nourish'. The current sense dates from the 1930s.[eutrophic etymology, eutrophic origin, 英语词源]