: any of various coarse brown algae (order Fucales, especially genera Fucus, Ascophyllum, and Silvetia) growing in marine environments free-floating or attached to rocks
Examples of rockweed in a Sentence
Recent Examples on the Web
In one, the boulder boasts a thick topper of rockweed.
—
J. Besl, Smithsonian Magazine, 8 June 2023
Her group was about to launch a restoration project for the olive rockweed, a species endemic to Laguna found nowhere else south of Santa Barbara.
—Los Angeles Times, 7 Oct. 2021
Wild harvesters typically bring in 14 to 20 million pounds of rockweed in a year.
—BostonGlobe.com, 1 May 2021
The state’s seaweed industry also includes a wild harvest of rockweed, which is used for livestock feed and fertilizers.
—From Usa Today Network and Wire Reports, USA TODAY, 21 Dec. 2020
This seaweed struggle, and the fate of A. nodosum itself, hinges on a single question, patently absurd yet bizarrely complex: is rockweed, in defiance of logic and biology, really a fish?
—Michelle Weber, Longreads, 1 June 2018
But rockweed does not fit easily into existing categories.
—Ben Goldfarb, Smithsonian, 31 May 2018
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J. Besl, Smithsonian Magazine, 8 June 2023
Her group was about to launch a restoration project for the olive rockweed, a species endemic to Laguna found nowhere else south of Santa Barbara.
—Los Angeles Times, 7 Oct. 2021
Wild harvesters typically bring in 14 to 20 million pounds of rockweed in a year.
—BostonGlobe.com, 1 May 2021
The state’s seaweed industry also includes a wild harvest of rockweed, which is used for livestock feed and fertilizers.
—From Usa Today Network and Wire Reports, USA TODAY, 21 Dec. 2020
This seaweed struggle, and the fate of A. nodosum itself, hinges on a single question, patently absurd yet bizarrely complex: is rockweed, in defiance of logic and biology, really a fish?
—Michelle Weber, Longreads, 1 June 2018
But rockweed does not fit easily into existing categories.
—Ben Goldfarb, Smithsonian, 31 May 2018
Cite this Entry
“Rockweed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rockweed. Accessed 4 Nov. 2025.
Copy CitationKids Definition
rockweed
noun
rock·weed
ˈräk-ˌwēd 
: any of various brown algae commonly growing attached to rocks along shores
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