A word that may owe its N to a medieval listening error — "an oche" misheard as "a noche" — the same process that created "nickname."
A V-shaped cut or indentation in an edge or surface, or a level or degree on a scale.
From Anglo-French noche or Old French oche meaning notch, possibly from a misdivision of the phrase une oche (a notch) heard as un noche Key roots: oche (Old French: "notch (with erroneous n- from article)").
Notch may owe its initial N to a common medieval error: mishearing "an oche" (a notch) as "a noche" — the N jumping from the article to the noun. The same process gave English the word nickname (originally "an ekename" misheard as "a nekename") and napkin (from "a naperon" misheard as "an apron" — going the other direction).