Jelly made from seaweed (4)

I believe the answer is:

agar

(Other definitions for agar that I've seen before include "What comes out of seaweed" , "Seaweed jelly" , "Jelly used in bacteria culture" , "Food thickener (derived from seaweed)" , "Substance derived from seaweed" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.