The Spanish word 'pescado' meaning 'fish (as food)' comes from Latin 'piscatus', meaning 'fished' or 'caught', which was the past participle of the Latin verb 'piscari' meaning 'to fish'. This Latin verb was derived from 'piscis', the Latin word for 'fish'. In Spanish, 'pescado' specifically refers to fish that has been caught and is ready to be eaten, as opposed to a living fish in the water.

A closely related and simpler Spanish word is 'pescar', which means 'to fish'. This verb comes from the same Latin root 'piscari'. While 'pescar' is the action of fishing, 'pescado' is the result - the fish that has been caught. This is a great example of how Spanish often uses the past participle of a verb as a noun to represent the result of an action.

While English 'fish' comes from a different Germanic root, there are some English words related to the Latin 'piscis'. These include 'piscine' (relating to fish), 'piscatorial' (relating to fishing), and 'pisces' (the astrological sign of the fish). The scientific term 'piscivorous', meaning 'fish-eating', also contains this Latin root.