Nori commonly eaten in South-East Asia and consists of red algae. The two most commonly used species are Porphyra yezoensis and Porphyra tenera. Red algae are rarely devoured fresh; they are instead dried and made into “paper”. Nori sheets can for instance be used in soups or for wrapping sushi.

Earlier, the word nori was used for a wide range of different seaweeds, including certain types of brown algae. One of the oldest mentioning of nori is from the 700s. The word nori is pronounced just like the Japanese word for glue; and algae is believed to have been used as glue as well as for food.