mush 2 
(mŭsh)
(mŭsh)v. mushed, mush·ing, mush·es
v.intr.
To travel, especially over snow with a dogsled.
v.tr.
To drive (a dogsled or team of dogs).
n.
A journey, especially by dogsled.
interj.
Used to command a team of dogs to begin pulling or move faster.
[Possibly alteration of French marchons, first person pl. imperative of marcher, to walk, go, from Old French; see MARCH1.]
musher n.