The Spanish word 'porqué' (meaning 'reason' or 'cause') is a compound word formed from two elements: 'por' and 'qué'. The first element 'por' comes from Latin 'per' meaning 'through' and 'pro' meaning 'before, in front of', which evolved into the Spanish preposition 'por' meaning 'for, by'. The second element 'qué' derives from Latin 'quid' meaning 'what'. When these elements combined, they formed 'porqué', literally meaning 'for what', which developed into the noun meaning 'reason' or 'cause'.

Some simpler, related Spanish words include the question word 'qué' (what) and the preposition 'por' (for, by). These are actually the two components that make up 'porqué'. Spanish learners might also encounter 'porque' (because) and '¿por qué?' (why?), which are closely related forms using the same elements but serving different grammatical functions.

While there aren't direct English cognates of 'porqué', English speakers might recognize the 'qué' part as being related to question words in English that come from the same Proto-Indo-European root, such as 'what', 'why', and 'which'. The 'por' element is related to English words containing 'per-' or 'pro-', such as 'percent' (through hundred), 'persist' (through-stand), and 'proceed' (go forward).