The Spanish word 'pasillo' (meaning 'corridor' or 'hallway') has its roots in Latin. It comes from the Latin verb 'pandere' meaning 'to extend or stretch', which gave rise to the Latin noun 'passus' meaning 'step' or 'pace'. This evolved into the Spanish word 'paso' (meaning 'step' or 'passage'). The diminutive suffix '-illo' was then added to 'paso' to form 'pasillo', literally meaning 'little passage', which came to specifically refer to a corridor or hallway in a building.

A simpler and more common Spanish word related to 'pasillo' is 'paso', meaning 'step' or 'passage'. While 'paso' refers to any kind of step or passage in a general sense, 'pasillo' specifically came to mean an indoor passageway or corridor. You might also encounter words like 'pasar' (to pass) and 'pasaje' (passage), which share the same Latin root.

Several English words are related to 'pasillo' through the shared Latin root 'passus'. These include 'pass', 'passage', and 'pace'. Just as 'pasillo' refers to a passage you can walk through, these English words all relate to movement or the act of passing. 'Pace' specifically retained the meaning of 'step' from the original Latin 'passus'.