glaucous UK /ˈɡlɔː.kəs/US /ˈɡlɑ.kəs/ adjective2 •Of a pale grey or bluish-green, especially when covered with a powdery residue.I realised I was the only shopper in that rather eerie place where I moved about fishlike, in a glaucous aquarium […] — 1955 •Covered with a bloom or a pale powdery covering, regardless of colour. formsmore glaucous · most glaucous