any brown seaweed of the genus Sargassum, esp S. bacciferum, having air bladders and forming dense floating masses in tropical Atlantic waters, esp the Gulf Stream
Also called: sargasso, sargasso weed
gulfweed in American English
(ˈgʌlfˌwid)
noun
1.
a brown algae (genus Sargassum) with berrylike air sacs, found floating in the Gulf Stream, Pacific Ocean, etc.