Tom yum or tom yam (Lao: ຕົ້ມຍຳ [tôm ɲam]; Thai: ต้มยำ, [tôm jam]) is a spicy clear soup typical in Laos and Thailand. Tom yum is widely served in neighbouring countries such as Malaysia, Singapore and Indonesia, and has been popularised around the world.
Literally, the words "tom yum" are derived from two Tai words: "tom" and "yam". "Tom" refers to boiling process (soup, in this case). "Yam" refers to a kind of Lao and Thai spicy and sour salad. Thus, "tom yum" is a Lao and Thai hot and sour soup. Indeed, tom yum is characterised by its distinct hot and sour flavours, with fragrant herbs generously used in the broth. The basic broth is made of stock and fresh ingredients such as lemon grass, kaffir lime leaves, galangal, lime juice, fish sauce and crushed chili peppers.