'Northolt' means the northern nook of land.
It was recorded in 872 as the Anglo-Saxon norð healum: norð is north, healum a nook, corner or retreat. The Domesday Book has Northala. The form Northolt appears by 1610, but its 'holt' has nothing to do with the word for a wood. In 1795 the historian Daniel Lysons noted that the ancient records almost all call the place Northall.