'varus' and 'valgus' originate from Latin, specifically the words 'varus' and 'valgus', where 'varus' meant 'bent inward/crooked' and 'valgus' meant 'knock-kneed/bent outward'.

'varus' and 'valgus' were terms in Classical Latin used to describe bent or deformed limbs; they were carried into Medieval and Medical Latin and later adopted into English medical terminology with the same technical meanings (e.g. 'genu varum', 'genu valgum').

Initially, they meant generally 'bent' or 'crooked' in Latin; over time their usage narrowed in medicine to the specific senses 'inward angulation' (varus) and 'outward angulation' (valgus).