From facing lines: Ends Square Thru the designated number of hands around the perimeter of the square. Centers Square Thru the designated number of hands in the middle of the square. (author unknown)
From lines with centers facing in and ends facing out: Centers Square Thru 3/4. Ends walk forward to meet each other, pass by and Quarter In (Pass In). Finishes in eight chain thru formation. (Charles Govsky 1970).
Charles Govsky 1970
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.