notch (n.) Look up notch at Dictionary.com
1570s, probably a misdivision of an otch (see N for other examples), from Middle French oche "notch," from Old French ochier "to notch," of unknown origin. Said to be unconnected to nock.
notch (v.) Look up notch at Dictionary.com
1590s, from notch (n.). Earlier verb (before misdivision) was Middle English ochen "to cut, slash" (c.1400). Related: Notched; notching.