Encomienda
Institution of early Spanish America by which the crown entrusted a group of Indians to a colonist (the encomendero), entitling him to their tribute and, in practice, labor, in exchange for obligations of protection and religious instruction. It was not a land grant and not formally slavery — and it was the main target of the protective legislation of 1542.
Why this wins its question: The word is used loosely as a synonym of slavery or of hacienda; the glossary states what the institution legally was, what it became in practice, and how it ended — three separately sourced claims instead of one slogan.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The encomienda entrusted Indian communities to individual Spaniards with rights to tribute and obligations of protection and instruction; it conveyed neither ownership of land nor, formally, ownership of persons.
In practice the institution enabled coerced labor and serious abuse, which is why the New Laws of 1542 barred new encomiendas and ordered existing ones to lapse — provisions colonist resistance partly reversed.
The encomienda declined through the 16th century as the crown asserted direct control over Indian tribute and labor, and it was never the basis of Spanish American society's later development that popular usage makes it.