graphite graphite /ˈgræˌfaɪt/

noun

1. () Used as a lubricant and as a moderator in nuclear reactors  ( black lead , plumbago , graphite )
   used as a lubricant and as a moderator in nuclear reactors
    The pencil's lead is made of graphite, a soft mineral that leaves a dark mark when rubbed against paper
   The pencil's lead is made of graphite, a soft mineral that leaves a dark mark when rubbed against paper