The Original Six are the six teams that comprised the NHL from 1942 to 1967, when the league expanded from six to 12 teams.
The name is not accurate. NHL membership fluctuated througout the 1920s and 1930s, as teams like the Ottawa Senators, Pittsburgh Pirates, Montreal Maroons and New York Americans came and went in the years prior to 1942.
The Original Six label appears to have gained currency with the league's expansion in 1967 and the years following.
The "Original Six" are: