From a wave, line or two faced line: Centers do a Tag Right and then Trade (Partner Trade or swing half) with the ends. Tip the Wave/Line Left means centers Tag Left before the Trade on the ends. A wave or two faced line finishes as a two faced line. A regular line finishes as a Three and One Line.
Joe Chiles 1976
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.