From the Latin word meaning ‘glory’, not used as a given name before the 20th century. It first occurs as the name of a character in George Bernard Shaw's play You Never Can Tell (1898), and was fairly popular in the 1940s and 1950s.
Scottish: regional name from Galloway in southwestern Scotland, named as ‘place of the foreign Gaels’, from Gaelic gall ‘foreigner’ + Gaidheal ‘Gael’. From the 8th century or before it was a province of Anglian Northumbria. In the 9th century it was settled by mixed Gaelic-Norse inhabitants from the Hebrides and Isle of Man.