Most people have a misunderstanding that there is a difference between activated carbon and activated charcoal. Both of these terms can and are used interchangeably. As well, active carbon is another similar word used for activated carbon and activated charcoal.
Activated charcoal tends to be the lay term. “Activated carbon” is more commonly used in the manufacturing/technical sectors. Other terms are activated coal. Sometimes “active” is substituted for “activated”.
Activated charcoal, granular activated carbon, granular active carbon – all different terms which just so happen to refer to one specific type of charcoal. Or, more accurately, it is charcoal reheated and oxidized, making the charcoal highly porous. Even though charcoal on its own is known for being a fairly porous substance, when oxidized (or, in some cases, carbonized with other inert gases) the amount of porous spaces increases significantly.