From waves or Alamo formations: Those who can turn half by the right, then those who can turn half by the left. Finishes in a wave or another Alamo formation. If called for facing pairs, they step forward and do the right arm turn first. GENERAL NOTE: If Swing Thru is called when dancers are in a Left-Hand wave, then the centers first turn half by the right (those who can) and the ends and adjacent dancers (neighbors) turn half by the left.
Del Coolman 1963
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.