Etymology

Verb

1. To rub a surface with a sharp object, especially by a living creature to remove itching with nails, claws, etc.

   Could you please scratch my back?

2. To rub the skin with rough material causing a sensation of irritation.

   I don't like that new scarf because it scratches my neck.

3. To mark a surface with a sharp object, thereby leaving; a scratch(noun).

   A real diamond can easily scratch a pane of glass.

4. To remove, ignore or delete.

   Scratch what I said earlier; I was wrong.

5. To produce a distinctive sound on a turntable, by moving a vinyl record back and forth while manipulating the crossfader. See scratching
6. To commit a foul in pool, as where the cue ball is put into a pocket or jumps off the table.

   Embarrassingly, he scratched on the break, popping the cue completely off the table.

7. A technical error of touching or surpassing the starting mark prior to the official start signal in the sporting events long jump (also called running broad jump), standing broad jump, discus, hammer throw, shot put, and similar events. Originally the starting mark was a scratch on the ground but now a board or precisely indicated mark.
8. To remove from a list.

   When the favorite was scratched from the race, there was a riot at the betting windows.

Noun

1. A disruption, mark or shallow cut on a surface made by scratching.

   I can’t believe there is a scratch in the paint already.

   Her skin was covered with tiny scratches.

2. A starting line.
3. A foul in pool, as where the cue ball is put into a pocket or jumps off the table.
4. money

   I need a little scratch.

Adjective

1. for or consisting of preliminary or tentative, incomplete, etc. work

   This is scratch paper, so go ahead and scribble whatever you want on it.

2. (via scratchpad) relating to a data structure or recording medium attached to a machine for testing or temporary-use purposes.