The term 'DANCE, WHEN DOUBLED' CAN be solved by two three-letter words: CAN and CHA. CAN is an abbreviation of the word 'cancan, ' which is a type of French dance that originated in the 19th century. It is characterized by high-energy, acrobatic movements and is often performed in a line. CHA is an abbreviation of the word 'CHA-cha, ' which is a Latin American dance that originated in Cuba in the 1950s. It is a partner dance that is known for its syncopated rhythms and distinctive hip movements.