fucus
noun
fu·cus ˈfyü-kəs 
1
obsolete : a face paint
2
[New Latin, genus name, from Latin] : any of a genus (Fucus) of leathery marine brown algae of rocky intertidal zones that are a source of algin and have been used as fertilizer
broadly : any of various brown algae compare rockweed
Example Sentences
Recent Examples on the Web The rocks draped with fronds of fucus seaweed beneath the tide line. 
Author: Brendan Jones, Alaska Dispatch News, 11 Aug. 2017
Author: Brendan Jones, Alaska Dispatch News, 11 Aug. 2017 Word History
Etymology
Latin, seaweed, archil, dye obtained from archil, from Greek phykos
First Known Use
1591, in the meaning defined at sense 1
Medical Definition
fucus
noun
fu·cus ˈfyü-kəs
1
capitalized : a genus (family Fucaceae) of cartilaginous brown algae used in the kelp industry
2
: any brown alga of the genus Fucus
broadly : any of various brown algae