An unplanned but obviously pre-choreographed outburst of dancing within a normal, non-party setting by a group of three or more people, usually including singing, as in most films classified as "musicals." Often abbreviated as SSD.
"In an attempt to avoid a fight which they knew they couldn't win, the smaller of the two gangs immediately broke into spontaneous synchronized dance, hoping the movements of their bodies and voices united in song would make the larger gang reconsider their course of action."
by Tom M. October 1, 2007