Irish Meaning: The name Fiona is an Irish baby name. In Irish the meaning of the name Fiona is: Fair. Scottish Meaning: The name Fiona is a Scottish baby name. In Scottish the meaning of the name Fiona is: Fair.he name Fiona is an American baby name. In American the meaning of the name Fiona is: Fair. Celtic Meaning: The name Fiona is a Celtic baby name. In Celtic the meaning of the name Fiona is: White or comely.