Usually, animacy has to do with how alive or how sentient a noun is. Humans, for instance, usually occupy a very high slot in an animacy hierarchy, only ever being ranked below deities or gods. Objects such as stones or grass may be ranked very low, and animals usually occupy a space in between; however, according to the spiritual beliefs of the people whose language possesses an animacy hierarchy, certain types of animal or plant may be ranked very highly in the hierarchy.
Examples of languages which possess animacy hierarchies include the Mexican language Totonac and the Navajo and Apache languages of the Athabaskan family, whose animacy hierarchy has been the subject of intense study.