1) English surname 
The surname (Mc)Gillick is a patronymic adopted by a branch of the Burkes of Connacht, and originates from the Irish Mag Uilic, meaning `son of Ulick`. Mag is a form of Mac (son) used in old Irish names before vowels. William is Uilliam in Gaelic, and `William the Younger` is Uilliam Og. As time passed, Uilliam Og was contracted to Uilleog, an...