a soft whitish calcite
"The geologist scraped a piece of chalk from the cliffside to analyze its soft, whitish calcite composition."
a pure flat white with little reflectance
"The artist mixed equal parts titanium white and chalk to achieve a pure flat white with little reflectance on the canvas."
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
"The doctor warned him that taking chalk without a prescription could dangerously overstimulate his nervous system."
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
"The teacher handed me a fresh piece of chalk so I could solve the math problem on the board."
A soft, white, powdery limestone.
"The geologist collected a sample of chalk to study its porous limestone structure."
In plain English: Chalk is a soft, white stone that breaks easily and leaves marks when you write with it on a blackboard or sidewalk.
"The teacher used chalk to write on the blackboard."
Usage: Use this term specifically for the soft limestone material or the marks made by it, rather than confusing it with similar-sounding words like "chalkboard." When referring to the substance used in sports or writing, ensure you distinguish between the powder itself and the solid stick form based on context.
write, draw, or trace with chalk
"The teacher wrote the math problem on the blackboard using a piece of white chalk."
To apply chalk to anything, such as the tip of a billiard cue.
"The player dipped the tip of his cue into the box and carefully applied chalk before taking his shot."
In plain English: To chalk something means to write on it using pieces of white powder made from limestone.
"The teacher chalked up another point to her final score before class ended."
A surname.
"My neighbor, Mr. Chalk, was elected to the school board last year."
The word chalk comes from Old English ċealc, which was borrowed from Latin calx meaning "limestone." This Latin term originally referred to a pebble in Ancient Greek before entering the Germanic language family.