Notch may be one of English's most entertaining etymological accidents. The word likely derives from Anglo-French noche or Old French oche (notch, groove), but the initial n- appears to have been acquired through misdivision — a process linguists call metanalysis. A speaker hearing the phrase une oche (a notch) could misinterpret it as un noche, reassigning the n from the article to the noun.
This process of false word-boundary assignment has produced several familiar English words. Nickname comes from an ekename (an additional name), misheard as a nekename. Apron comes from Old French naperon (a small tablecloth), with the n moving from the noun to the article: a naperon became an apron. Umpire comes from Old French nonper (non-equal, one
The notch as a physical mark — a V-shaped cut in an edge — is one of humanity's oldest information-recording techniques. Before writing, notches cut into tally sticks recorded numerical information: debts, transactions, quantities, and counts. The medieval English Exchequer (treasury) used tally sticks with notches to record tax payments until 1826. When Parliament ordered
The figurative use of notch to mean a level or degree — to take it up a notch, top notch — derives from the practice of marking graduated scales with notches. Belt notches, gun notches, and measuring stick notches all use the V-shaped cut as a unit of measurement or counting.
The phrase 'to notch up' (to achieve, to score) and 'notch on one's belt' (a recorded achievement) extend the metaphor of the tally mark into the vocabulary of accomplishment. Each notch represents a completed task, a victory, or a milestone.