Tamari is a type of soy sauce, usually used in Japanese food. You can easily substitute with Chinese Light Soy or regular Japanese soy sauce.
This is the fruit pod of trees originally from Africa, now common in Asia, India, and the West Indies. The taste is bittersweet with citrus overtones. The pulp is very sticky and difficult to work with. Common forms sold are syrups and bricks of the pulp. It is used extensively in dishes of these regions as well as in candy and drinks.