sargassum

noun

sar·​gas·​sum sär-ˈga-səm 

: any of a genus (Sargassum) of brown algae that have a branching thallus with lateral outgrowths differentiated as leafy segments, air bladders, or spore-bearing structures : gulfweed

Examples of sargassum in a Sentence

Recent Examples on the Web

Sun Sentinel Record-breaking seaweed in Atlantic could mean stinky beaches in South Florida Levels of floating seaweed mats, known as sargassum, have skyrocketed in the Atlantic Ocean in the past month, with the total amount breaking the record for March. —South Florida Sun Sentinel, Sun Sentinel, 2 Apr. 2025

Researchers think the Gulf will start to see more sargassum in the coming weeks. —Bill Kearney, Sun Sentinel, 1 Apr. 2025

The report said that during the last week of December, small amounts of sargassum had already reached the Lesser Antilles. —Bill Kearney, Sun Sentinel, 14 Jan. 2025

The hatchlings then drift in the open ocean, clinging to floating sargassum and feeding on small organisms found in the seaweed. —Smithsonian Magazine, 7 Mar. 2025

Word History

Etymology

borrowed from New Latin, borrowed from Portuguese sargaço sargasso

First Known Use

circa 1890, in the meaning defined above

Kids Definition

sargassum

noun

sar·​gas·​sum sär-ˈgas-əm 

: any of a genus of brown algae that have a leafy branching body and air bladders and that often grow in free-floating masses in the ocean