Scientific and general term for red algae, a phylum of mostly marine algae often used in food and industry.
Tengusa, a type of red algae, is used to make agar.
Red algae contain phycoerythrin as a photosynthetic pigment.
red algae; Rhodophyta
Compound of 紅 (kō, 'crimson, red') + 藻 (sō, 'algae, seaweed'). The kanji directly reflect the characteristic red color of these algae.