Notch is a narrow route between mountains. It also means A V-shaped cut, or a small cut (nick). A notch is also a degree or a level: For example, he will always remain a notch or two ahead from you in his work.

Notch would mean one of the units in the stage: as on increasing or decreasing scale, or degree, or level, or step, grade etc. For example, in the football score- team A defeated team B by a notch.

A notch is a gap, or a little hole which could have occurred by mistake or could have been created deliberately for a particular purpose. For example, a knife can get a damaged or may become notched when it hits something harder. This would be by accident.
For example, there are notches in a walking stick to increase or decrease the length of the stick according to convenience.