From facing lines: Lines Walk In--Center four do a quarter of a Grand Square (walk forward and then face the centers) as the ends Pass Thru and Quarter In. Finishes in new facing lines. Lines Walk Out--Centers Pair Off (walk forward and face out) as the ends Pass Thru and Quarter Out. Finishes in lines facing out.
Deuce Williams 1969
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.