seaweed

noun

sea·​weed ˈsē-ˌwēd 

1

plural seaweeds : any of various aquatic and chiefly marine brown, red, or green algae (such as rockweed, gulfweed, and kelp) that often grow in masses, typically have leaflike blades (see blade entry 1 sense 2e), are usually anchored to a solid substrate (such as a rock) by holdfasts (see holdfast sense 2a), and include some (such as dulse, laver, and sea lettuce) that are used as food

… many seaweeds have floats called pneumatocysts, filled with oxygen or carbon dioxide.

—Michael Le Page

The word seaweed is broad and refers generally to marine macroalgae, which are algae living in salt or brackish water and visible to the eye.

—Elyse Inamine

2

: a mass or growth of seaweeds

… soft crabs were easily visible in the seaweed, because the water was crystal clear then.

—Keith Walters

3

: harvested seaweed or seaweed parts used especially as food, fertilizer, and in cosmetics

… sushi rolls wrapped in thin sheets of dried seaweed …

—Jane Snow

Examples of seaweed in a Sentence

Recent Examples on the Web

To mitigate their emissions, meat and dairy companies are pinning their hopes on a suite of technological solutions including adding seaweed to cattle feed or implementing manure digesters: massive pools meant to capture methane from livestock poop, for use as a fuel source. —Grace Van Deelen, Vox, 11 July 2024

What about mushroom leather, seaweed fiber, prosciutto purses and fruit skin silk suits? —Lauren Parker, Sourcing Journal, 9 July 2024

Satellite images showed the seaweed swath reached a record size for December, more than twice the average size of patches seen in previous Decembers, said Chuanmin Hu, a professor of optical oceanography at the University of South Florida. —Dinah Voyles Pulver, The Enquirer, 12 June 2024

Its soft pleats cradle the fish, sheathed in a batter made from three flours and vodka for maximum crunch, and latticed with powdered seaweed to give the appearance of tiny green veins. —Bill Addison, Los Angeles Times, 9 July 2024

Word History

First Known Use

1577, in the meaning defined at sense 1a

Kids Definition

seaweed

noun

sea·​weed -ˌwēd 

: a plant growing in the sea

especially : a marine alga (as a kelp)