Here's how it evolved:
* Palatinus (Latin) referred to something or someone belonging to the palace.
* Palatin (Old French) was a derivative of palatinus and meant "a count or noble".
* Pal (Middle English) evolved from palatin and began to be used as a term of endearment, meaning "friend" or "companion".
So, while the word's origin is Latin, it went through a journey through Old French and Middle English before becoming the familiar "pal" we know today.