Adam Jack Aitken (1921–1998) was a Scottish lexicographer.
Jack Aitken was born in
Edinburgh, grew up in Bonnyrigg, Midlothian, and was educated at Lasswade High School. After serving in the Royal Artillery during World War II, he returned to the University of Edinburgh to continue his teaching career and to research the origins of the Scots and Celtic languages.
Sir William Craigie in the compilation of the Scottish National Dictionary and The Dictionary of the Older Scottish Tongue, now available online as the Dictionary of the Scots Language. After Craigie he took over The Dictionary of the Older Scottish Tongue as editor and completed the first of those in 1976. Aitken also instigated a new reading program of ancient manuscripts and historic papers in order to increase the reach and accuracy of the dictionary. Upon completion in 2000 the dictionary was dedicated to him.
Aitken is also well known for his formulation of the
Scottish Vowel Length Rule, also known as Aitken's Law. He also developed a numbering system for the Scots vowels which enabled a better understanding and description of the historical development of those.