|1.||a V-shaped cut or indentation; nick|
|2.||a cut or nick made in a tally stick or similar object|
|3.||(US), (Canadian) a narrow pass or gorge|
|4.||informal a step or level (esp in the phrase a notch above)|
|5.||to cut or make a notch in|
|6.||to record with or as if with a notch|
|[C16: from incorrect division of an otch (as a notch), from Old French oche notch, from Latin obsecāre to cut off, from secāre to cut]|
An indentation at the edge of a structure; an incisure.
An upstroke or peak on a pulse tracing.