The Spanish word 'copa' meaning 'cup' comes from Late Latin 'cuppa' meaning 'cup', which itself developed from Latin 'cupa' meaning 'cask' or 'tub'. The evolution from a large container (cask/tub) to a smaller drinking vessel shows how words can narrow or specialize in meaning over time. The change from 'cuppa' to 'copa' reflects common sound changes as Latin evolved into Spanish, where 'u' often became 'o' and double consonants were simplified.

A related Spanish word is 'cubeta' (bucket or pail), which also comes from Latin 'cupa'. While 'copa' evolved to refer to a smaller drinking vessel, 'cubeta' maintained a meaning closer to the original Latin word's sense of a larger container.

English speakers might recognize the connection to words like 'cup' and 'cuppa' (informal British English for a cup of tea), which share the same Latin ancestor 'cuppa'. The English word 'coop' (as in chicken coop) is also related, coming from Latin 'cupa', reflecting the original meaning of a container or enclosed space.