A greeting card is an illustrated, folded card that expresses friendship or other sentiments. Greeting cards are commonly given on special occasions like birthdays and holidays but can also be used to convey thanks or other feelings. There are many types of greeting cards including standard cards, photo cards, personalized cards, reusable cards, risque cards, musical cards, and electronic cards with specific cards made for occasions like birthdays, Christmas, weddings, and Mother's Day.