I. ˈ ̷ ̷ˌ ̷ ̷ noun
Etymology: Middle English horsback, from hors horse + back
1. : the back of a horse
2.
a. : a natural ridge of sand, gravel, or rock : hogback
b. : a mound, ridge, bank, or parting of barren rock in a coal seam
II. adverb
: on horseback