The Spanish word 'angelito' (meaning 'little angel') comes from combining the Spanish word 'ángel' with the diminutive suffix '-ito'. The word 'ángel' itself can be traced back to Latin 'angelus' (meaning 'angel'), which was borrowed from Ancient Greek 'ángelos' (ἄγγελος) meaning 'messenger'. The Greek word originally referred to any kind of messenger, but through its use in religious contexts to refer to divine messengers, it developed its current meaning of 'angel' in Latin and subsequently in Spanish.

The most obvious related Spanish word is 'ángel' (angel), which is the base word from which 'angelito' is formed. The suffix '-ito' is a very common Spanish diminutive that you'll see in many words to indicate smallness or endearment, like in 'perrito' (little dog) or 'gatito' (little cat).

The English word 'angel' is closely related to 'angelito', as it comes from the same Latin 'angelus' and Greek 'ángelos' roots. You can also see this root in English words like 'angelic' and 'archangel'. Understanding this connection can help you remember that 'angelito' essentially means 'little angel' in Spanish.