Definition of sit & go
A sit & go is similar to a tournament. Unlike a tournament, it will not start at a fixed time, but when there is a quorum. A sit & go has a predefined number of players. There are 2-player, 6-, 9-, 12-, 18-, 180-, 360-, etc. sit & goes. Sit & go formats are added year after year. What differentiates a tournament from a sit & go is that it will start when the number of entries is filled. The structure will be determined in advance and generally, sit & gos will have a structure that favours the first places. In other words, the money in the total prize pool will be concentrated in the top 3 places.
Sit & gos, an excellent school!
If you are new to online poker, sit & gos will be a great school for you to learn. You'll be able to control your spending better than in cash games because in cash games, if you have a bad streak, you never know how much it might cost you in your evening. Sit & gos are fixed in price and have a shorter duration than tournaments which can sometimes stretch over several days.