The Spanish word 'osa' meaning 'female bear' comes directly from the Latin word 'ursa', which also meant 'female bear'. During the evolution from Latin to Spanish, the 'ur' sound simplified to 'o', and the final 'a' remained unchanged, as it typically does in feminine nouns from Latin to Spanish.

A common related Spanish word is 'oso' (male bear), which follows the same etymology but with the masculine ending '-o'. The word appears in several Spanish expressions, like 'oso hormiguero' (anteater, literally 'ant bear') and 'oso polar' (polar bear).

While English 'bear' comes from a different root, we can find the Latin 'ursa' in several English words. The most notable is 'ursine', meaning 'bear-like' or 'relating to bears'. The constellation 'Ursa Major' (Great Bear) and 'Ursa Minor' (Little Bear) also preserve this Latin root. The chemical element 'uranium' was named after the planet Uranus, which in turn was named following the celestial naming pattern that included Ursa Major.