Mar·mite /ˈmɑːmaɪt $ ˈmɑːr-/ trademark a type of soft, dark brown substance with a strong salty taste, which is a yeast extract. It is usually spread on bread in small quantities, but it can also be used to give taste to soups. It is a typically British food, sold in a round brown glass container. There is a similar product sold in Australia called Vegemite.