The term card (from Greek χάρτης - chartēs, "paper, papyrus"), primarily refers to cardboard or a piece of this.

More generally, the term can refer to any of various small flat objects, typically made from heavy paper or plastic. In particular:

• Business card, a wallet sized card containing contact information for a person or business
• Bank card aka ATM card refers to a plastic card issued by a bank and used to access funds from an account
• Credit card, a plastic card for purchasing items on credit
• Debit card, a plastic card for purchasing items using money in a bank account
• Cigarette card, a trading card used to reinforce cigarette packaging
• Common Access Card (CAC), a Department of Defense (DoD) access & ID Card; contains a computer chip.
• Digital Tachograph Card a plastic card for the European Union Driving Licence
• Expansion card or computer card, a computer hardware component or device, attached generally inside a computer, that provides added functionality, such as a graphics card or sound card
• File card (tool), a metal brush used to clean the cutting grooves on files
• Flashcard, a card with questions and answers written on it, used as a learning aid
• Gift card, usually plastic payment tool that is mailed or given to a relative, friend, or associate as a method of purchasing within stores
• Green card, an identification card for permanent non-citizen US residents
• Greeting card, usually folded paper that is mailed or given to a relative, friend, or associate to express a message of greeting, appreciation, or some other sentiment
• Health card, a token to be used as patient data card (PDC) or health professional card (HPC)
• Identification card, an identity document
• Index card, a card for creating and organizing notes in a stack, usually for a research project
• Keepsake card a plastic card (Souvenir) some things with a Poem on it
• Keycard while not actually considered a key, is a plastic card which stores a digital signature that is used with electronic access control
• Library card, a card used to borrow books or other media from a library
• Memory card, a data storage device used with digital cameras, computers, telephones, music players, video game consoles, and other electronics
• Penalty cards for rule violations in several sports, e.g. red card or yellow card
• Photocard Driving Licence a plastic card for the United Kingdom's European Union Driving Licence
• Playing card, a card, typically made of laminated paper, used for playing games
• Policy debate card, a piece of evidence in policy debate
• Passport card an alternative to a passport created in the United States to meet the documentary requirements of the Western Hemisphere Travel Initiative.
• Pilot Card required for an individual to act as a pilot of an aircraft
• Postcard, a card used for sending messages in the mail without use of an envelope
• Proof of Age Card a plastic card to prove that bearer is over 18 years old (21 in some places)
• Punch card, an obsolete method for storing data
• Raising card, a spiked brush-like tool used to straighten out wool, hemp, etc.
• Subscriber Identity Module Card,(SIM Card) a smart card identifying a mobile phone service subscriber
• Smart card, a plastic card containing a computer chip
• Time card, a card used to record a worker's hours of employment
• Trading card, a card used for trading or collecting, or for use in a collectible card game
• Value card, a self-help device listing behavior changes the bearer wants to make
• Visiting card, aka calling card, a more personal version of a business card
• Voter registration card the requirement in some democracies for citizens and residents to check in with some central registry specifically for the purpose of being allowed to vote in elections.
• Warrant Card a proof of identification and authority carried by Police Officers.
• Wild card originally used in card games, but the term has evolved to describe an unknown or unpredictable factor in any number of domains
• Work card is like an Identity Card which verifies that a person has been given work, or is eligible to perform work in a given profession or jurisdiction.