caste
n. countablen. a social group that someone is born into and cannot change. It is often used to describe strict social levels in certain cultures or groups of animals like ants.
n. a hereditary social class or group within a rigid hierarchy, often defined by occupation or ritual purity. In biological contexts, refers to a specialized group within a colony of social insects that performs a specific functional role.
The worker ants belong to a specific caste in the colony.
In some traditional societies, your caste determines which jobs you are allowed to perform and who you can marry.
The evolutionary success of social insects depends on the physiological differentiation of each caste, allowing the colony to operate as a single, highly efficient organism.
Borrowed from Portuguese or Spanish casta (“lineage, breed, race”), which the OED derives from Portuguese casto (“chaste”), from Latin castus (“chaste"; "chastity”), Coromines (1987) argues instead for a hypothetical Gothic form 𐌺𐌰𐍃𐍄𐍃 (kasts, “group, collection of animals”), cognate with English cast, from Proto-Germanic kastuz, from Proto-Indo-European h₂ǵ-es-.
Commonly used in sociological contexts to describe rigid stratification or in entomology to describe social insect roles.