Nouns

(n)castesocial status or position conferred by a system based on class“lose caste by doing work beneath one's station”
(n)caste(Hinduism) a hereditary social class among Hindus; stratified according to ritual purity
(n)castea social class separated from others by distinctions of hereditary rank or profession or wealth
(n)castein some social insects (such as ants) a physically distinct individual or group of individuals specialized to perform certain functions in the colony