The Spanish verb 'pescar' (to fish) comes from the Latin verb 'piscari', which also meant 'to fish'. The Latin 'piscari' itself was derived from the Latin noun 'piscis' meaning 'fish'. During the evolution from Latin to Spanish, the 'i' in 'pisc-' changed to 'e', giving us 'pesc-', which is a common sound change pattern between Latin and Spanish words.

Several common Spanish words share this Latin root, including: 'pez' (fish), 'pescado' (fish - specifically as food), and 'pescador' (fisherman). The word 'pesca' (fishing) is also directly related, being the noun form of the verb 'pescar'.

While English 'fish' comes from a different Germanic root, there are several English words that share the Latin 'piscis' ancestry with 'pescar'. These include 'piscine' (relating to fish), 'piscatorial' (relating to fishing), and 'pisces' (the astrological sign of the fish). These tend to be more formal or technical terms in English, while the Spanish 'pescar' is an everyday word.