The Irish name may be derived from words meaning "cloud", "passionate", "victory", "honour" or "champion".
[1] As a surname, Neil is traced back to Niall of the Nine Hostages who was an Irish king and eponymous ancestor of the Uí Néill and MacNeil kindred.
[2] The name also entered Northern England and Yorkshire directly from Ireland, and from Norwegian settlers.
As a first name, during the Middle Ages, the Gaelic name of Irish origins was popular in Ireland and later Scotland.
Some Scottish McNeills returned to Ireland in the 14th century and are associated with MacNeill, MacGreal, MacReill, and Mag Reil surnames.