Synonyms for Notch:

n.

channel, cranny, cavity, aperture, crater, blowhole. point, rung, big, the march of something, history, direction, momentum, a giant step/leap/stride, progress, stage, peg, advance, maturation, advancement, development. finely, cut-up, etch, chop, cut out, clip. blemish (noun)
lesion, blotch, impurity, drawback, fault, stigma, brand, scab, rift, eyesore, deformity, sore, abrasion, weal, distortion, spoilage, imperfection, wart, discoloration, disfigurement, defacement.
degree (noun)
caliber, degree, potential, amplitude, magnitude, level, extent, scale, grade, intensity, quality, range, step, measure.
gap (noun)
gulf, abyss, cleft, interval, breach, crevice, space, chasm, gap, break, ravine.
indentation (noun)
mark, cleft, groove, nick, cut, incision, scratch, gash, indent, gap, score.
level within classification (noun)
step, stage, grade, rung, degree.
nock (noun)
groove.
notch (noun)
nick, serration, mountain pass, split, pass, incision, indent, indentation, cut, jog, snick, chink.
unit of measurement (noun)
degree.

v.

blemish (verb)
scuff, distort, blemish, gash, disfigure, mark, spoil, deform, deface, dot, hurt, check, fracture, taint, nick, defect, scar, slit, mar, stain, speck, score, damage, discolor, splotch, abrade, freckle, scrape, fleck, blot, hack, tarnish, blister, scratch, chip, kink, pockmark, flaw, spot.
indent (verb)
incise, cleave.
notch (verb)
incise, cleave, serrate.

Other synonyms:

rung, peg. point. stage. channel
groove.
Other relevant words:
big, peg, momentum, stage, point, etch, advance, direction, advancement, mountain pass, clip, groove, finely, progress, blowhole, cavity, history, development, snick, channel, aperture, rung, cranny, pass, crater, chop, maturation.

Usage examples for notch

  1. Make a little notch on the key- board by which he can easily find middle C. Then let him relieve his pent- up soul by the painting of sound- pictures. – The Rosary by Florence L. Barclay
  2. Even while Ward lifted his rifle and got the ivory bead snugly fitted into the notch of the rear sight with his eye, he would not have bet two- bits that he was aiming at an animal. – The Ranch at the Wolverine by B. M. Bower