Definition of walk
A walk in poker is something that can only happen to you when you are in the big blind. A walk is when all the players before you have folded and therefore you win the blinds without even having to play the hand. Since all the players have folded before you, you don't need to show your hand, you just collect the pot.
Tournament walks
You will probably get more walk in tournaments than in cash games. For example, if you have a very aggressive tournament image and you are the table leader in chips, it is quite possible that you will get a lot of walk. Players, in the absence of a hand, will not dare steal your blind. They will think that you are very aggressive and that you will not let it happen. Also, since you will have a big stack, you will be more likely to call. This is a good reputation to have in this situation since in reality you won't always be able to defend your precious blinds in tournaments. A walk is always a good thing when you are in the big blind (except when you have a monster of course).
