What's the difference between countermarch and countermarching?
Countermarch
Definition:
(v. i.) To march back, or to march in reversed order.
(n.) A marching back; retrocession.
(n.) An evolution by which a body of troops change front or reverse the direction of march while retaining the same men in the front rank; also, a movement by which the rear rank becomes the front one, either with or without changing the right to the left.