The Spanish verb 'jugar' (meaning 'to play') comes from the Latin verb 'iocari', which meant 'to jest' or 'to play'. This Latin verb was derived from the noun 'iocus', meaning 'joke' or 'jest'. Over time, as Latin evolved into Spanish, the meaning broadened from specifically jesting or joking to encompass all forms of playing and gaming. The spelling changed from 'iocari' to 'jugar' following regular sound changes from Latin to Spanish, where the initial 'io-' became 'ju-'.

Some related Spanish words include 'juego' (game), 'juguete' (toy), and 'jugador' (player). All these words share the same Latin root and maintain the core concept of play and entertainment.

The English word 'joke' is actually related to 'jugar', as both come from the Latin 'iocus'. While Spanish developed the meaning more towards general play and games, English retained the more specific meaning of something funny or humorous. Other related English words include 'jocular' (playful, humorous) and 'jest', which all preserve the original Latin sense of playful humor.