chalk chalk /ˈtʃɔk/

noun

1. 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  ( chalk )
   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
    Can you please pass me the chalk so that I can write on the blackboard?
   Can you please pass me the chalk so that I can write on the blackboard?
   
   
2. [Informal] 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  ( chalk [Informal] , chicken feed , crank [Informal] , deoxyephedrine , glass [Informal] , ice [Informal] , meth [Informal] , methamphetamine , methamphetamine hydrochloride , Methedrine , shabu [Informal, Asia] , trash [Informal] , crystal meth , gak [Informal] )
   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
   
   
3. A pure flat white with little reflectance  ( chalk )
   a pure flat white with little reflectance
   
4. A soft whitish calcite  ( chalk )
   a soft whitish calcite
    The teacher used a piece of chalk to write the day's lesson on the blackboard.
   The teacher used a piece of chalk to write the day's lesson on the blackboard.
   
   

verb

1. Write, draw, or trace with chalk  ( chalk )
   write, draw, or trace with chalk