In NetHack and/or AD&D (and probably other RPGs as well), a charge is an untapped "use" of a certain class of magical items. These items can only be used a certain number of times in their magical fashion (for example, a chime of opening), as opposed to permanent magical items, which can be used indefinitely (such as a bag of holding). Items which rely on charges can usually be recharged by some complicated process (or a scroll of charging, depening on the game).

In NetHack, all wands are charged, as well as several other items (tinning kits, magic markers, etc).