n. A back like that of a hog; a back which rises in the middle.n. A fish in which the back is humped some-what like a hogā² s.n. A low, sharply crested ridge rising upon the adjacent region, and usually formed of sand or gravel with boulders intermixed: in New England more commonly called horseback. Compare horseback, eskar, kame.n. In coal-mining, a sharp rise in the floor of a coal-seam.n. A hog-frame.Resembling a hog's back in form: used specifically in describing a small locomotive which is very low in build and has no cab.