Ouilly is an element in several place-names in Calvados, Lower Normandy, France:

Ouilly-le-Vicomte Ouilly-le-Tesson Ouilly-du-Houley Pont-d'Ouilly

d'Ouilly is the origin of the English surnames d'Oyly and Doiley:

The D'Oyly baronets, a number of British baronetcies. Richard D'Oyly Carte, Victorian theatrical impresario

This surname is further given to:

D'Oyly Carte Island, an island in the River Thames, England. The doily, an ornamental table mat supposedly invented by a Mr Doiley