Seaweed is a term for multiple varieties of marine algae. This includes some members of the red, brown and green algae. Seaweeds can also be classified by their use (as food, medicine, fertilizer, industrial, etc.).
Seaweeds are extensively used as food by coastal people, particularly in East Asia, e.g. Japan, China, Korea, Taiwan, Thailand, and Vietnam, but also in Indonesia, Belize, Peru, the Canadian Maritimes, Scandinavia, Ireland, Wales, Philippines, and Scotland, among other places.
In Asia, Zicai (in China), gim (in Korea) and nori (in Japan), sheets of dried Porphyra are used in soups or to wrap sushi.
Chondrus crispus (commonly known as Irish moss or carrageenan moss) is another red alga used in producing various food additives, along with Kappaphycus and various gigartinoid seaweeds.
Chinese crispy seaweed
Despite its name, Chinese crispy seaweed is not seaweed at all, but prepared cabbage, fried in spices.