From WordNet (r) 2.0 (August 2003) [wn]:
hogback
n : a narrow ridge of hills [syn: horseback]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Hogback \Hog"back`\, n.
1. (Arch.) An upward curve or very obtuse angle in the upper
surface of any member, as of a timber laid horizontally;
-- the opposite of camber.
[1913 Webster]
2. (Naut.) See Hogframe.
[1913 Webster]
3. (Geol.) A ridge formed by tilted strata; hence, any ridge
with a sharp summit, and steeply sloping sides.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Hogframe \Hog"frame`\, n. (Steam Vessels)
A trussed frame extending fore and aft, usually above deck,
and intended to increase the longitudinal strength and
stiffness. Used chiefly in American river and lake steamers.
Called also hogging frame, and hogback.
[1913 Webster]