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

The National Oceanic and Atmospheric Administration’s new daily sargassum inundation risk map shows high risk levels of sargassum along the Florida Keys on Thursday, May 21. — Bill Kearney, Sun Sentinel, 22 May 2026

Researchers said sargassum is not currently classified as a food source, and more research and funding will be needed before products using it can receive regulatory approval. — Bri Buckley, CBS News, 12 May 2026

Experts estimate about 10 million metric tons of sargassum are floating in the Atlantic, now covering South Florida beaches. — Bri Buckley, CBS News, 12 May 2026

This January, satellite images showed some of the largest masses of sargassum ever for that month, according to Chuanmin Hu of University of South Florida, who pioneered satellite tracking of sargassum using NASA data. — Ashley Miznazi, Miami Herald, 11 May 2026

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