The Spanish word 'sexo' (meaning 'sex') comes from the Latin word 'sexus', which meant 'biological sex' or 'gender'. Interestingly, 'sexus' itself derives from the Latin verb 'secare', meaning 'to cut' or 'to divide'. This etymology reflects the ancient concept of dividing or separating humans into distinct biological categories.

Some related Spanish words include 'sexual' (sexual), 'sexista' (sexist), and 'sexualidad' (sexuality). These words all share the same Latin root and form a family of words related to biological sex and gender.

English speakers will recognize many cognates with 'sexo', including 'sex', 'sexual', 'sexist', and 'sexuality'. These words all come from the same Latin root 'sexus'. Additionally, the root 'secare' (to cut) is found in English words like 'section', 'dissect', and 'intersect', all of which involve the concept of cutting or dividing.