The Spanish word 'grifo' meaning 'tap' or 'faucet' (and alternatively 'griffin') comes from Late Latin 'gryphus', which meant 'griffin'. This in turn derives from Ancient Greek 'grýps' (γρύψ), also meaning 'griffin' - the mythical creature that was part eagle and part lion.

The semantic shift from 'griffin' to 'faucet' in Spanish is believed to be due to the common decorative use of griffin heads in fountains and water spouts, particularly during medieval and Renaissance periods. Over time, the word for the decorative griffin head came to refer to the water spout or tap itself.

While 'grifo' itself is a relatively common Spanish word, there aren't many simpler or more common Spanish words that share its etymology. The word maintains both its original meaning referring to the mythical creature 'griffin' and its more common modern meaning of 'tap' or 'faucet'.

The English word 'griffin' (or 'gryphon') is directly related to 'grifo', as they both come from the same Greek root 'grýps'. While the Spanish word evolved to commonly mean 'faucet', the English word retained its original meaning of the mythical creature. This connection can help English speakers remember that 'grifo' historically referred to griffin decorations on water spouts.