What a veToken is
A veToken, short for vote-escrow token, is what you get when you lock a protocol's governance token for a fixed period. You give up access to the token for weeks, months, or years, and in return you receive voting power and rewards that scale with how long you lock. The model started with Curve's veCRV and has since been copied across DeFi.
Why lock at all
Locking is a filter. It rewards the people willing to commit to a protocol over the ones who would sell at the first dip. The longer you lock, the more voting weight and the larger the reward boost you get, so the loudest voices in governance are also the ones with the most at stake for the longest time.
What holders actually get
A veToken position usually earns several things at once: a boost on your liquidity-provider rewards, a share of the protocol's trading fees, and voting power over where token emissions are directed. That last part is valuable enough that a market grew around it, where other projects pay veToken holders to vote emissions toward their pool. Those payments are called bribes, or more politely, vote incentives.
Common examples
The pattern shows up as veCRV on Curve, veBAL on Balancer, and vePENDLE on Pendle. The details differ, but the trade is the same everywhere: lock now in exchange for influence and yield later.