Definition of "Caste" :

noun: in some social insects (such as ants) a physically distinct individual or group of individuals specialized to perform certain functions in the colony

noun: a social class separated from others by distinctions of hereditary rank or profession or wealth

noun: (Hinduism) a hereditary social class among Hindus; stratified according to ritual purity

noun: social status or position conferred by a system based on class

"Lose caste by doing work beneath one's station."