(card games) A card that can be assigned any value or used to substitute for any needed card.

(Commonwealth of Nations) A police identification card, sometimes accompanied by a badge.

(computing) A piece of hardware installed into a personal computer to allow it to send video signals to an external output device such as a monitor or projector.

A card set down at a table to inform a guest (named on the card) where they are to sit.

(computer hardware) A solid state digital memory storage format, commonly found on computers, digital cameras and cellphones.

(poker, chiefly in the plural) A playing card, dealt face down, that the holder need not reveal until the showdown / (by extension) Something held in reserve, or concealed, until it is useful

A person who uses card counting in pontoon or blackjack in order to obtain an advantage.

A strategy, in pontoon or blackjack, in which a player keeps a mental tally of the cards played in order to calculate the probability of certain cards being dealt and therefore obtain an advantage.

(US) A US work permit, officially known as United States Permanent Resident Card.

Enrolled as a member of an organization, and having a card to prove it; loyal to that organization or the cause it supports. / (by extension) Loyal and dedicated to some cause. / Official.