abbreviation of TAM-O-SHANTER.
1895. Daily News, 8 April, 6/7. The Tams as the Tam OShanters are now universally called by shopkeepers, are favourites for windy weather.
1896. Godeys Mag., Feb., 224/2 The headgear is a coquettish white Tam with a white quill.
1899. Annie E. Holdsworth, Valley Gt. Shadow, x. Ill put on your tamthere!
1918. Independent, XCV. 20 July, 102, photo caption. One of the Ladies from Hell is trying to keep his Tam on and connect with a fast one from the pitcher at the same time.