'Hendon' means the high hill, or at the highest hill.
The Anglo-Saxon name Hendun is older than the Domesday survey, which describes the manor. Hendon is first mentioned in a charter claimed to date from 972–8; by then a settlement had presumably grown up at Church End, on a well-watered rise where the parish church stands. Yet the hills around – Mill Hill, Hampstead, Finchley and Harrow – are all significantly higher.