
Spanish word piso comes from Proto-Indo-European *peys-
*peys- (Proto-Indo-European)
pinsare (Latin)
pisar (Spanish)
(intransitive) to step; to walk; to tread. (transitive) to walk on (something); to tread on (something). (vulgar, Cuba, El Salvador, Dominican Republic, intransitive, transitive) to have sex, fuck.
piso (Spanish)
(Chile) carpet. (Chile) footstool. Decker (bus, bed). Flat, apartment. Floor. Story, storey (level of a building).