(Celtic or Gaelic.) The son of a dog; figuratively, the son of a champion. The Britons, Celts, and Gauls, applied the names of various animals to their heroes, indicative of strength, endurance, courage, or swiftness. This name is derived from Mac, son, and cu, kei, or ki, a wolf—dog. The common hound was called Gayer.

The surname McKay is of Scots origin, coming from the Scots Gaelic MacAoidh which means ‘son of Aodh’. The original meaning of the first name Aodh remains uncertain, but the most probable translation is ‘fire’. This would thus have been a nickname, referring probably to the temperament (or possibly the complexion or hair-colour) of the holder. Another possible translation of Aodh is ‘inspiration’. This original first name is another possible origin for some instances of the popular first names of Hugh and Hugo.

The McKays originally came from the far north of Scotland, and from Inverness-shire. The origin of the main northern McKays is obscure, but they may well have come from the legendary Clann Morgan. The Inverness-shire McKays usually write their name in Gaelic as MacAi. This further complicates the origin of the name, for MacAi in Scots Gaelic is a form of MacDhai, which translated as ‘Davidson’ (the Scots Gaelic Dhai being similar to the popular Welsh first name ‘Dai’).

As is usual with names that have been translated from the Gaelic through the ages, there have been countless variations on this name in the records. These range from Mackhe (1538) to Macky (1513) and M’Akie (1559). This variation gave rise to the ancient Stirlingshire name of Mackie, and thus Mackieson. This popular form means ‘son of the son of —’. The more common Macpherson is not the same-this comes from the Gaelic Mac an Phearsain, meaning ‘son of the parson’.

The earliest mention of any version of McKay comes in the 1098 Manx records. Here one Cucail Mac Aedha is mentioned. However, it is not until 1326 that we find the more recognisable name Gilchrist M’Ay, who is listed by George Black, the eminent expert on Scottish names.

The American colloquialism ‘the real McCoy’ (meaning ‘genuine’, ‘best of its kind’) originated through a mix-up over a brand of whisky called McKays exported to the US in the 1880s. The company slogan was confused with the name of an American boxer named McCoy.

Scotsman James Mackay explored the Missouri River and pushed on to the Pacific coast, drawing up the map later used by the famous Lewis and Clark expedition.

The enormous multi-national company International Telephone and Telegraph (IT&T) was founded by Clarence Hungerford MacKay (1874—1938) who supervised the completion of the first trans-Pacific cable between the United States and the Far East (1907).

The largest clipper ship ever built, the Great Republic, 4,555 tons, was produced by master Boston shipbuilder Donald McKay (1810—80). Not only did he make them big; he made them fast. His boatyard’s ship Lightning had a top speed of 21 knots and established a long-standing record of 436 nautical miles in 24 hours.

The only two towns named McKay are in Australia and the United States. Australia has a MacKay Lake, Canada has 2 (one spelled MacKay) as well as a McKay river. Australia has a MacKay mountain and a McKay mountain range.

With about 25,000 namesakes MacKay and McKay form Scotland’s 18th most popular surname. Thus about one out of every 208 Scots is named MacKay or McKay. (The name is not common enough throughout England and Wales to be counted separately.) MacKay and McKay are notably popular in and around both Edinburgh and Glasgow; in each an estimated one in about 240 families bears the name. Around the world this surname is most common in Wellington (one in 562 families), Canberra (one in 622), Vancouver (one in 694) and Auckland (one in 732). The United States has 11,000 MacKays and 41,000 McKays-in combination making this their 527th most popular surname.