From two columns of two side by side (facing the same way or in opposite directions): Lead person in each file of two walks forward to cross to the other side and face in on the end of a newly forming line. Trailing person in each file follows the leader to the other side and faces in as the center of the new line. Finishes in a line of four (if the files both face the same way) or in a two-faced line (if the files face opposite to each other). NOTE: Jim first named this "Cross to a Line" in 1961 and then the name "Trail Off" was applied to it. It is a "Cross Peel Off" movement.
Jim Gammalo 1962
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.