noun

1. a white, gray, or yellowish limestone that is soft, porous, and easily pulverized, composed almost entirely of calcite from minute sea shells
2. any substance like chalk in color, texture, etc.
3. a piece of chalk, often colored, used for drawing, writing on a blackboard, etc.
4. a mark or line made with chalk
5. Brit. a score or tally, as in a game or as of credit given

Etymology: ME < OE cealc < L calx, lime, limestone: see calcium

adjective

1. made or drawn with chalk
2. ☆ Horse Racing, Slang
   1. favored to win, place, or show
   2. betting on favorites only

transitive verb

1. Brit. to treat with chalk; lime or fertilize (soil)
2. to rub or smear with chalk; specif., to rub chalk on the tip of (a billiard cue)
3. to make pale
4. to write, draw, or mark with chalk

intransitive verb