A Notch

1. A V-shaped cut.
   1. Such a cut, used for keeping a record.
2. An indentation.
3. A mountain pass; a defile.
4. (slang) The female primary sex organ, vulva.
5. (US slang) A woman.
6. (finance) A discontinuous change in a taxation schedule.
7. (informal) A level or degree.
8. (electronics) A portion of a mobile phone that overlaps the edge of the screen, used to house a camera, sensors etc. while maximizing screen space.