Meaning & use
alga
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Meaning
nouncountablebiology
A simple plant-like organism that lives in water or damp places and makes its own food from sunlight, with no true roots, stems or leaves.
Grammar: Singular only; the plural is algae: one alga, many algae.
Patterns
- an alga in something
Under the microscope, we could see a single green alga.
Each alga in the pond uses sunlight to make food.
Seaweed is a large kind of alga.
Word forms
| plural | algae |
|---|
Common combinations
- a single-celled alga
- A single-celled alga floated through the drop of water.
- a green alga
- The green alga covered the stones in the stream.
- a marine alga
- A marine alga called kelp grows very tall.
- a toxic alga
- A toxic alga caused the beach to be closed.
Synonyms and how they differ
Word family
- algae noun
- the plural form, also used for the group
- algal adjective
- relating to algae
- algicide noun
- a chemical that kills algae
- algology noun
- the scientific study of algae
Commonly confused: alga or algae? alga or fungus?
alga vs algae
Algae is the plural; alga is the singular for one organism.
alga vs fungus
A fungus cannot make its own food from sunlight, but an alga can.
Practice
What is the plural of alga?
Choose one answer.
Alga comes from Latin and takes the plural algae. Algas looks like a regular plural but is not the standard form.
Make it your own
Write a sentence using “alga”, then check it and compare it with the examples above.