Poker is a group of card games that involve trying to get a good hand of cards. Usually there is some betting, and people give or take cards to try to build a better hand.
The three of us play poker every Friday night, and the loser buys drinks.
(countable) A poker, which people also call a fire poker or fire iron, is something people use in a fire. They use it to move around the ashes so that the fire keeps burning well, and they use it to move coals back to the middle of the fire.
The fire is dying down, so can you hand me the poker?