The Spanish word 'adulterio' (meaning 'adultery') comes from the Latin word 'adulterium' with the same meaning. This Latin term was derived from the verb 'adulterare' meaning 'to corrupt or adulterate', which was formed by combining two elements: the Latin prefix 'ad-' (meaning 'toward') and the verb 'alterare' (meaning 'to alter'). The verb 'alterare' itself came from the Latin word 'alter' meaning 'other'. So etymologically, the concept of adultery was understood as the act of 'turning toward another' or 'corrupting oneself with another.'

Some related Spanish words that share this etymology include 'alterar' (to alter or change), 'otro' (other), and 'alternar' (to alternate). These words all trace back to the Latin 'alter' meaning 'other', showing how the basic concept of 'otherness' or 'change' runs through these related terms.

English speakers can easily connect 'adulterio' with the English word 'adultery', as they share the same Latin root 'adulterium'. Other related English words include 'adulterate' (to corrupt or make impure by adding other substances), 'alter' (to change), and 'alternate' (to occur by turns). All these words share the fundamental concept of 'changing' or 'turning to something other than the original.'