postcard or post card is a typically rectangular piece of thick
paper or thin cardboard intended for writing and mailing without
an envelope and at a lower rate than a letter. It is distinguished
by stamp collectors from a postal card in that the postage is
pre-printed on the latter, whereas a postcard requires a stamp.
While a postcard is usually printed by a private company, individual
or organization, a postal card is issued by the relevant postal
In the art world the postcard can also be translated into an art
object. The art form is called mail art.
The study and collecting of postcards is termed deltiology.
Some activists create oversized postcards on poster boards urging
action on a particular issue and mail them to public officials'
offices. The idea is that it stands out and cannot be filed away
in a folder somewhere.