A greeting card is an illustrated piece of card stock or high quality paper featuring an expression of friendship or other sentiment. Although greeting cards are usually given on special occasions such as birthdays, Christmas or other holidays, such as Halloween, they are also sent to convey thanks or express other feelings (such as to get well from illness). Greeting cards, usually packaged with an envelope, come in a variety of styles. There are both mass-produced as well as handmade versions that are distributed by hundreds of companies large and small. While typically inexpensive, more elaborate cards with die-cuts or glued-on decorations may be more expensive.
Hallmark Cards and American Greetings, both U.S.-based companies, are the two largest producers of greeting cards in the world today.
In Western countries and increasingly in other societies, many people traditionally mail seasonally themed cards to their friends and relatives in December. Many service businesses also send cards to their customers in this season, usually with a universally acceptable non-religious message such as "happy holidays" or "season's greetings".