Definition of shove
A "shove" is a synonym for all in. When a player is said to be "shoving his stack", he is pushing all his chips into the middle of the table and is therefore all in. You may hear phrases like "Do you like my shove on the river?" or "Do you think I should have shoved on the river? We always talk about pushing your stack in this situation.
The word shove and its many synonyms
If you are a regular in the poker rooms or chat rooms of online poker rooms, you know that there are several synonyms to express the same idea. To describe the action of putting all your chips or all your money in the middle of the table, you can use several expressions: a shove, an all in, go all-in, a jam, a snap push, a push, "I bombed him on the river", "I sent him all in", "I pushed all in", "I sent all the sauce", "I sent the rubber in", etc. And that was just a sampling of the expressions you will hear. In short, a shove is an all in!