# seaweed

/ˈsiˌwid/ (US) · /sˈiːwiːd/ (UK) · CEFR B1 · Noun

Source: https://englishreference.com/word/seaweed
Updated: 2026-05-07

## Definition

plants that grow in the sea or on rocks by the ocean. You can find it on the beach, and some types are used in cooking.

For teachers: large algae growing in the sea or on rocks below the high-water mark. Often used as a collective term for various marine macroalgae.

## Examples

- The beach was covered in green seaweed after the storm.
- Many coastal cultures harvest seaweed to use as a nutrient-rich ingredient in soups and salads.
- Marine biologists are studying how certain species of seaweed can sequester carbon dioxide more efficiently than land-based forests, potentially mitigating the effects of climate change.

## Usage notes

- Uncountable when referring to the plant material in general; countable when referring to specific biological species.

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