Lao adj 1: of or relating to a member of the Buddhist people inhabiting the Mekong river in Laos and Thailand n 1: a member of a Buddhist people inhabiting the area of the Mekong River in Laos and Thailand and speaking the Lao language; related to the Thais [syn: {Lao}, {Laotian}] 2: the Tai language of a Buddhist people living in the area of the Mekong River in Thailand and Laos