The Spanish verb 'calar' (meaning 'to penetrate' or 'to sink') traces its origins back to Ancient Greek through Late Latin. It comes from the Greek word 'khaláo' (χαλάω), which meant 'to loosen' or 'let down'. This Greek word evolved into the Late Latin 'chalare', meaning 'to lower' or 'descend'. From there, it developed into the modern Spanish 'calar', where the meaning shifted slightly to focus on the action of penetrating or sinking into something.

A common related Spanish word is 'calado' (the past participle of calar), which is used as an adjective meaning 'soaked through' or as a noun meaning 'draught' (of a ship). You might also encounter 'caladura', meaning 'perforation' or 'hole'. These words all maintain the core concept of something penetrating or sinking into something else.

While there aren't many common English words directly related to 'calar', the nautical term 'chalant' (though rare) comes from the same Greek root and refers to a ship that is lowering or descending in the water. The concept of 'lowering' from the original Greek 'khaláo' is preserved in this technical term.