What is the meaning of Sideboard?

A piece of dining room furniture having drawers and shelves for linen and tableware; originally for serving food.

A board or similar barrier that forms part of the side of something.

A set of cards that are separate from a player's primary deck, used to customize a match strategy against an opponent by enabling a player to change the composition of the playing deck.

A restriction on using the right to catch a certain number of fish that was granted in relation to a different fishery.

To include (a card) in one's sideboard.

To add sideboards to.

a sideboard

Source: wiktionary.org