The Spanish word 'periquito' (parakeet) has an interesting etymology that traces back to the Greek name 'Petros' (Πέτρος), meaning 'stone' or 'rock'. This Greek word evolved into the Latin name 'Petrus', which then became the Spanish name 'Pedro' (Peter). A variant form of Pedro was 'Pero', which led to 'perico' meaning 'small parrot'. Finally, the diminutive suffix '-ito' was added to 'perico' to form 'periquito', literally meaning 'little parrot'.

This pattern of using personal names for animals is not uncommon in Spanish and other languages. Just as English speakers might call a parrot 'Polly', Spanish speakers began using derivatives of 'Pedro' to refer to these birds, perhaps because parrots can mimic human speech and were often given human names.

The most closely related Spanish word is 'perico', which refers to a larger parrot or parakeet. This word is actually the base from which 'periquito' is derived. Both words are ultimately derived from 'Pedro', the Spanish name for Peter. You might also encounter 'Pero', an old variant of Pedro, though it's less common in modern Spanish.

While 'periquito' itself doesn't have direct English cognates, its distant ancestor, the Greek 'Petros', is the source of several common English words. The most obvious is the name 'Peter', which comes from the same Greek root. Other related English words include 'petrify' (to turn to stone), 'petroleum' (literally 'rock oil'), and 'salt peter'. All these words share the connection to the original Greek meaning of 'stone' or 'rock'.