H to the Usky Husky came up with it when casting a game.  It describes the standard terran 1/1/1 build which is 1 barracks, 1 factory and 1 starport.

I can't recall which game it was but here is his channel:

[Husyky's Youtube channel][1]


  [1]: http://www.youtube.com/user/HuskyStarcraft