The Official (and Unofficial) guide to Poker Tournament Formats
SNG - Sit and Go (The tournament will start when the seats are full rather than at a set time)
STT - Single Table Tournament (usually a SNG)
MTT - Multi-table Tournament - (Starts at a fix time and is usually has no limit on entrys)
HU - Heads Up - 1 player vs 1 player. The winner progressing to the next round
Freezeouts - Any tournaments where rebuys arent allowed
Rebuys - If you get knocked out you can re-enter.
Shootouts - tournament is played in rounds. 1 table plays down to 1,2 or 3 players. Then this (or these) player(s) progress to the next round, where the same happens. It is a bit like a series of STTs
Satellite/Feeder - The tournament is a qualifying tournament for a bigger tournament
Steps - These are a mix of shootouts and satellite. Each single table tournament you win, you will progress to the next step up. The goal being to complete all steps and qualify for an expensive tournament.
Turbo/Speed - The blinds go up quicker than normally leading to much faster play, and alot more left to chance.
Deep Stack - More starting chips and slower blinds than normal, leading to a much more skillful game, but a game which requires alot of patience and endurance.
Shovament/Flipament (inf.) - All-in every hand until you get a winner . The ultimate in poker lottery craziness.