card one of a set of small pieces of stiff paper marked in various ways and used for playing games or for telling fortunes; "he collected cards and traded them with the other boys"
lettercard a postcard that folds so the message is inside
A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope. In some places, it is possible to send them for a lower fee than for a letter. Stamp collectors distinguish between postcards (which require a stamp) and postal cards (which have the postage pre-printed on them).
OmegaWiki Dictionary
Ω
postcard A rectangular piece of paper intended for mailing; it contains a picture on one side and a place for a message and a post stamp on the other side
postcard A rectangular piece of thick paper or thin cardboard intended to be written on and mailed without an envelope.
