credit card
A card one uses to make purchase on credit, usually containing magnetic stripes to be read by computer systems.
The concept of credit cards is in which one buys goods & services first, paying off the costs later (and varying amounts of interest, usually on a monthly basis). First introduced in the US during the 50s, the widespread of them since then allowed for greater growth of the economy, although it also driven up household debt in the meantime. Most people in the developed world has at least one these days, usually several. Many credit card companies offer various reward points for their costumers in order to encourage spending. Some companies charge a transaction fee onto merchants, which made certain businesses to not accept them.