uncle: [13] Uncle comes via Anglo-Norman uncle and late Latin aunculus from Latin avunculus ‘mother’s brother, maternal uncle’ (source also of English avuncular [19]). This was a diminutive noun derived from the prehistoric base *aw- ‘grandparent’, and it has relatives in Latin avus ‘grandfather’, Welsh ewythr ‘uncle’, Polish wuj ‘uncle’, Armenian hav ‘uncle’, etc. => avuncular[uncle etymology, uncle origin, 英语词源]