The Spanish word 'pata' (meaning 'paw' or 'animal leg') traces back to the Latin verb 'pangere', which meant 'to fix, fasten, or plant'. This evolved into the Latin word 'pacta' meaning 'fixed' or 'planted'. In Vulgar Latin, this developed into '*patta', which took on the specific meaning of 'foot' or 'leg of an animal'. The connection between 'fixing/planting' and 'animal leg' likely comes from the idea of an animal's legs being firmly planted on the ground. This word eventually evolved into the modern Spanish 'pata'.

A related Spanish word is 'pato' (duck), which likely shares the same root due to ducks being notable for their distinctive legs/feet. Another related term is 'patada' (kick), which is directly derived from 'pata' since it refers to an action done with the leg or foot.

While not directly related to 'pata', English words like 'pace' and 'pass' come from the same Latin root 'pangere'. These words maintained more of the original sense of movement or fixing in place. The word 'pact' is also related, coming from 'pacta', and retained the meaning of something fixed or agreed upon.