seaweed

American  

[see-weed] / ˈsiˌwid /

noun

1. any plant or plants growing in the ocean.

2. a marine alga.

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seaweed British  

/ ˈsiːˌwiːd /

noun

1. any of numerous multicellular marine algae that grow on the seashore, in salt marshes, in brackish water, or submerged in the ocean

2. any of certain other plants that grow in or close to the sea

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seaweed Scientific  

/ sē′wēd′ /

1. Any of various red, green, or brown algae that live in ocean waters. Some species of seaweed are free-floating, while others are attached to the ocean bottom. Seaweed range from the size of a pinhead to having large fronds (such as those of many kelps) that can be as much as 30.5 m (100 ft) in length. Certain species are used for food (such as nori) and fertilizer, and others are harvested for carrageenan and other substances used as thickening, stabilizing, emulsifying, or suspending agents in industrial, pharmaceutical, and food products. Seaweed is also a natural source of the element iodine, which is otherwise found only in very small amounts.

2. See more at brown alga green alga red alga

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Etymology

Origin of seaweed

First recorded in 1570–80; sea + weed ¹

Compare meaning

How does seaweed compare to similar and commonly confused words? Explore the most common comparisons:

• algae vs. seaweed

Example Sentences

As they feed on seaweed and seagrass, they trim back algae and help protect slow-growing species such as corals and certain calcifying algae.

From Science Daily

Archaeologists made their first exploration in summer 2022, but had to wait till the following winter – when the seaweed had died back – before they could map the wall properly.

From BBC

To evaluate the effect of seaweed, researchers built controlled crawlways on the sand that simulated each hatchling's natural route.

From Science Daily

Some strategies use biological processes, such as increasing plankton or seaweed growth so they can take up carbon dioxide as they develop.

From Science Daily

These fossils are among the earliest known seaweeds in the geological record, dating to a time when most organisms were visible only under a microscope.

From Science Daily

Related Words

• algae