Noun borer has 2 senses
  1. bore bit, borer, rock drill, stone drill - a drill for penetrating rock
    --1 is a kind of drill
    --1 has particulars: cross bit; star drill; straight flute, straight-fluted drill
    Derived form: verb bore2
  2. woodborer, borer - any of various insects or larvae or mollusks that bore into wood
    --2 is a kind of invertebrate
    Derived form: verb bore2