scratch

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To make a thin shallow cut or mark on (a surface) with a sharp instrument.
• intransitive verb To use the nails or claws to dig or scrape at.
• intransitive verb To rub or scrape (the skin) to relieve itching.
• intransitive verb To scrape or strike on an abrasive surface.
• intransitive verb To write or draw (something) by scraping a surface.
• intransitive verb To write or draw hurriedly.
• intransitive verb To strike out or cancel (a word, for example) by or as if by drawing lines through.
• intransitive verb Slang To cancel (a project or program, for example).
• intransitive verb To withdraw (an entry) from a contest.
• intransitive verb To use the nails or claws to dig, scrape, or wound.
• intransitive verb To rub or scrape the skin to relieve itching.
• intransitive verb To make a harsh scraping sound.
• intransitive verb To gather funds or produce a living with difficulty.
• intransitive verb To withdraw from a contest.
• intransitive verb Games To make a shot in billiards that results in a penalty, as when the cue ball falls into a pocket or jumps the cushion.
• noun A mark resembling a line that is produced by scratching.
• noun A slight wound.
• noun A hasty scribble.
• noun A sound made by scratching.
• noun Sports The starting line for a race.
• noun A contestant who has been withdrawn from a competition.
• noun The act of scratching in billiards.
• noun A fluke or chance shot in billiards.
• noun Poultry feed.
• noun Slang Money.
• adjective Done haphazardly or by chance.
• adjective Assembled hastily or at random.
• adjective Sports Having no golf handicap.
• idiom (from scratch) From the very beginning.
• idiom (scratch the surface) To investigate or treat something in superficial or preliminary fashion.
• idiom (up to scratch) Meeting the requirements.
• idiom (up to scratch) In fit condition.

from The Century Dictionary.

• To mark or wound slightly on the surface by the scraping or tearing action of something rough, sharp, or pointed.
• To rub or scrape, as with the finger-nails or with a scratcher, but without wounding or marking, as for the purpose of relieving itching or irritation.
• To write or draw hurriedly or awkwardly; scribble.
• To dig, scrape, or excavate with the claws: as, some animals scratch holes in which they burrow.
• To erase or blot out; obliterate; expunge.
• Specifically
• In horse-racing, to erase, as the name of a horse, from the list of starters.
• In United States politics, to erase (the name of a candidate on a printed ballot) by drawing a line through it; hence, to reject (a candidate).
• Synonyms Chafe, Abrade, etc. See scrape.
• To use the nails, claws, or the like for tearing the surface, or for digging, as a hen.
• To relieve cutaneous irritation by the scraping action of the nails or claws or of a scratcher.
• In United States politics, to expunge or delete a name on a voting-paper or ballot; reject one or more candidates on a regular party ticket, by canceling their names before casting the ballot.
• In billiards, to make a scratch or fluke.