Meaning

noun a V-shaped indentation

noun the location in a range of mountains of a geological formation that is lower than the surrounding peaks

noun a V-shaped or U-shaped indentation carved or scratched into a surface

originRecorded since 1577, probably a rebracketing of an otch, from Middle French oche (“notch”), itself from the Old French verb ochier (“to notch”), of uncertain origin, but possibly related to French hocher and English nick (“small cut, notch”).

Etymology from Wiktionary, CC BY-SA 3.0