phaeo·phy·ce·ae \ˌ ̷ ̷ ̷ ̷ˈfīsēˌē, -fis-\noun plural Usage: capitalized Etymology: New Latin, from phaeo- + -phyceae in some classifications: a class comprising the brown algae and being coextensive with the division Phaeophyta • phaeo·phy·cean\| ̷ ̷ ̷ ̷|fishən\adjective or noun • phaeo·phy·ceous\-shəs\adjective