Caste
mid 16th century (in the general sense ‘race, breed’): from Spanish and Portuguese casta ‘lineage, race, breed’, feminine of casto ‘pure, unmixed’, from Latin castus ‘chaste’.
wiktionary
Borrowed from Portuguese or Spanish casta(“lineage, breed, race”), of uncertain origin. The OED derives it from Portuguese casto(“chaste”), from Latin castus. Coromines (1987) argues instead for a hypothetical Gothic form *𐌺𐌰𐍃𐍄𐍃( *kasts), cognate with English cast, from Proto-Germanic *kastuz.
etymonline
caste (n.)
"one of the hereditary social groups of India," 1610s from Portuguese casta "breed, race, caste," earlier casta raça, "unmixed race," from Latin castus "cut off, separated" (also "pure," via notion of "cut off" from faults), past participle of carere "to be cut off from," from PIE *kas-to-, from root *kes- "to cut." Caste system is first recorded 1840. An earlier, now-obsolete sense of caste in English is "a race of men" (1550s), from Latin castus "chaste."
Of the castes, the first three are the natural and gradually established divisions of the Aryan invaders and conquerors of India; the fourth was made up of the subjugated aborigines. The Sanskrit name for caste is varna, color, the different castes having been at first marked by differences of complexion, according to race, and in some degree according to occupation and consequent exposure. [Century Dictionary, 1895]
