Blazer. A bright colored, loose summer coat, usually of striped flannel, worn by tennis and cricket players. The origin of the word is as follows: The boat club's uniform at St. John's College is bright red, and the St. Johnian jackets have for many years been called blazers, on account of being of such fiery color. Up to a few years ago the inaccurate modern term of blazer for a jacket of any other colorthan red, was unknown.