A postcard is a piece of card with a photo on the front. It has space on the back to write a message to a family member or a friend, space for a stamp, and space to write the address of the person you are sending it to. Postcards do not need envelopes.
People usually send postcards when they are on holiday to tell their friends or family about the place they have visited, what they have been doing, and what they plan to do. Sometimes people just send postcards to let somebody know they are thinking about them.
