chalk

A soft, white, powdery limestone (calcium carbonate, CaCO₃).

A piece of chalk, or nowadays processed compressed gypsum (calcium sulfate, CaSO₄), that is used for drawing and for writing on a blackboard (chalkboard).

Tailor's chalk.

A white powdery substance used to prevent hands slipping from holds when climbing, or losing grip in weight-lifting or gymnastics, sometimes but not always limestone-chalk, often magnesium carbonate (MgCO₃).

(US) The favorite in a sporting event.

(US) The prediction that there will be no upsets, and the favored competitor will win.

(US) A platoon-sized group of airborne soldiers.

To record something, as on a blackboard, using chalk.

To use powdered chalk to mark the lines on a playing field.

(figurative) To record a score or event, as if on a chalkboard.

To apply chalk to anything, such as the tip of a billiard cue.

To manure (land) with chalk.

To make white, as if with chalk; to make pale; to bleach.