Board
The community cards on the table at any moment of a hand.
Players describe a board by its texture. A "dry" board such as K72 has few draws. A "wet" or "coordinated" board such as J108 has many straight and flush possibilities.
Board texture changes how you should bet. On wet boards strong hands usually bet bigger to charge draws. On dry boards smaller bets often do the same job.
Example
On a paired board like 883, a full house or four of a kind becomes possible.