Definition of "Lao" :

noun: the Tai language of a Buddhist people living in the area of the Mekong River in Thailand and Laos

noun: 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

adjective: of or relating to a member of the Buddhist people inhabiting the Mekong river in Laos and Thailand