These were largely obsoleted by the invention and subsequent adoption of Trade By movements. They all stem from the original movement Barge Thru (by Manny Amor, Lakewood, NJ) which, from facing lines of four, requires dancers to do a Half Square thru then those facing out to do a Partner Trade and those facing in to Pass Thru. The movement ends in eight chain thru formation. Barge Thru can now be called as "Half Square thru then Trade By."
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.