ridge: [OE] Old English hrycg denoted ‘the back’, as its modern Germanic relatives – German rücken, Dutch rug, Swedish rygg, and Danish ryg – still do. But a gradual semantic focussing on the ‘backbone’ led by the 14th century to the emergence of ‘long narrow raised area’, today’s main meaning. It goes back to a prehistoric Germanic *khrugjaz, which may have been related to Sanskrit krunc- ‘be crooked’ – in which case the notion underlying the word would be of a ‘bent back’.
ridge (n.)
Old English hrycg "back of a man or beast," probably reinforced by Old Norse hryggr "back, ridge," from Proto-Germanic *khrugjaz (cognates: Old Frisian hregg, Old Saxon hruggi, Dutch rug, Old High German hrukki, German Rücken "the back"), of uncertain origin. Also in Old English, "the top or crest of anything," especially when long and narrow. The connecting notion is of the "ridge" of the backbone. Spelling with -dg- is from late 15c. Ridge-runner "Southern Appalachian person" first recorded 1917.
