A carousel was a children's attraction, which was usually located at an amusement park, and consisted of a rotating platform with wooden horses on which to ride.
A small indoor carousel, with horses as well as a unicorn, was part of Jean-Luc Picard's family home as he imagined it while in the Nexus. (Star Trek Generations)
Love was compared to a carousel in the song "Just in Time". A children's carousel was also mentioned in the song "I'll Be Seeing You". (DS9: "It's Only a Paper Moon")