'polygenic' originates from Greek, specifically from the elements 'poly-' (from Greek 'polús') meaning 'many' and '-genic' (from Greek root 'gen-' / 'génēs') meaning 'born' or 'origin'.

'polygenic' changed from the Neo-Latin/scientific formation 'polygenicus' and was adopted into modern English usage as 'polygenic', especially in 19th–20th century biological literature.

Initially it carried the general sense of 'having many origins' or 'produced from many sources', but over time it evolved into the specialized modern meaning 'involving or produced by multiple genes'.