The Spanish verb 'permitir' (meaning 'to permit' or 'to allow') comes from the Latin verb 'permittere', which had the same meaning of 'to allow' or 'let pass through'. The Latin word 'permittere' was formed by combining two elements: the prefix 'per-' meaning 'through' or 'completely', and the verb 'mittere' meaning 'to send'. So literally, the original concept was about 'sending something through' or 'letting something pass through completely', which evolved into the more general meaning of allowing or permitting.

Several common Spanish words share the same Latin root 'mittere' (to send). These include: 'meter' (to put in, insert), 'remitir' (to send, remit), 'transmitir' (to transmit), 'admitir' (to admit), and 'emitir' (to emit). All these words carry some sense of movement or sending, though each has developed its own specific meaning.

Many English words are related to 'permitir' through the same Latin roots. The most obvious is 'permit', which shares both meaning and etymology. Other related English words include 'mission' (from mittere, 'to send'), 'transmit', 'admit', 'emit', 'submit', and 'remit'. The prefix 'per-' is also found in many English words like 'perfect' (completely done), 'persist' (continue through), and 'permeate' (pass through).