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• noun A contestant who has been withdrawn from a competition.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.

• noun A break in the surface of a thing made by scratching, or by rubbing with anything pointed; a slight furrow; a score: as, a scratch on wood or glass.
• noun A slight wound; a laceration; a slight incision: as, he escaped with a mere scratch on the face.
• noun plural A disease in horses, consisting of dry chaps, rifts, or scabs between the heel and the pastern-joint.
• noun In various contests:
• noun The line from which the contestants start.
• noun A line drawn across a prize-ring, to which boxers are brought in order to join fight. See to come up to the scratch, under come.
• noun The starting-point or time of starting of a player or contestant who has to make the full score or who is allowed no odds in a handicap game or contest; also, a player or competitor holding such a position.
• noun In billiards, a stroke which is successful, but not in the way intended; a fluke.
• noun A kind of wig covering only a part of the head; a scratch-wig.
• noun A calcareous, earthy, or stony substance which separates from sea-water in boiling it for salt.
• noun A scrawl.
• Taken at random or haphazard, or without regard to qualifications; taken indiscriminately; heterogeneous: as, a scratch crew.
• Without handicap or allowance of time or distance: noting a race or contest in which all competitors start from the same mark or on even terms, or a competitor who receives no handicap allowance.