A list of dance partners. Although the youth of today may find it hard to believe, there was a time when couples that went to a party or a dance danced with other people. This was especially true at proms, cotillions, and balls. In order for a woman, and not just the belle of the ball, to keep track of her partners, she entered their names on a dance card, a small booklet issued by the event's organizers that was attached to the wrist or dress with a thin cord. It was then up to the gentlemen to remember their partners for the evening (men often kept their own lists). As a marginally polite but pointed way to brush someone off, you might smile and say, “I'd love to, but my dance card is filled."