1. A soft compact calcite, CaCO3, with varying amounts of silica, quartz, feldspar, or other mineral impurities, generally gray-white or yellow-white and derived chiefly from fossil seashells.
2. A piece of chalk or chalklike substance in crayon form, used for marking on a blackboard or other surface.
3. games A small cube of chalk used in rubbing the tip of a billiard or pool cue to increase its friction with the cue ball.
4. A mark made with chalk.
5. chiefly british A score or tally.
6. to mark, draw, or write with chalk: chalked my name on the blackboard.
7. to rub or cover with chalk, as the tip of a billiard cue.
8. to make pale; whiten.
9. to treat (soil, for example) with chalk.
10. chalk up to earn or score: chalk up points.
11. chalk up to credit or ascribe: chalk that up to experience.

1. A soft, white, powdery limestone.
2. A piece of chalk, or, more often, processed compressed chalk, that is used for drawing and for writing on a blackboard.
3. tailor's chalk.
4. A white powdery substance used to prevent hands slipping from holds when climbing, sometimes but not always limestone-chalk.
5. A platoon-sized group of airborne soldiers.
6. the prediction that there will be no upsets, and the favored competitor will win.
7. to apply chalk to anything, such as the tip of a billiards cue.
8. to record something, as on a blackboard, using chalk.
9. to use powdered chalk to mark the lines on a playing field.
10. to record a score or event, as if on a chalkboard.

1. A soft, earthy substance, of a white, grayish, or yellowish white color, consisting of calcium carbonate, and having the same composition as common limestone.
2. finely prepared chalk, used as a drawing implement; also, by extension, a compound, as of clay and black lead, or the like, used in the same manner. see crayon.
3. to rub or mark with chalk.
4. to manure with chalk, as land.
5. to make white, as with chalk; to make pale; to bleach.

1. to rub or mark with chalk.
2. to manure with chalk.
3. figuratively, to make chalky-white; blanch; make pale.
4. to mark; trace out; describe: from the use of chalk in marking lines.
5. in scotland, to mark the door of a burgh tenant with chalk, an old mode of notice to quit, which is still competent.
6. in geology, a soft white rock, consisting almost entirely of carbonate of lime in a pulverulent or only slightly consolidated state, and readily soiling the fingers when handled.
7. A piece of prepared chalk used for marking on a dark surface.
8. A point scored in a game: so called from its being recorded with chalk.
9. an account. see to chalk up, below.
10.
11. in geological nomenclature the term chalk has been employed with a variety of meanings. in the english subdivisions of the cretaceous system the chalk constitutes the upper part of this system, resting on the Galt and Greensand, which in turn lies on the basal division or Wealden.

1. a pure flat white with little reflectance
2. a soft whitish calcite
3. a piece of calcite or a similar substance, usually in the shape of a crayon, that is used to write or draw on blackboards or other flat surfaces
4. an amphetamine derivative (trade name Methedrine) used in the form of a crystalline hydrochloride; used as a stimulant to the nervous system and as an appetite suppressant
5. write, draw, or trace with chalk