Colony counter /(kŏl"ō̇*ny̆ kount"ẽr)/

Col·o·ny count·er

Colony counter

n.
  1. an instrument designed to conveniently count or assist counting colonies{9} of microorganisms on a plate containing a gelled growth medium. One variety uses a pencil-like rod with a metal tip, which is connected by an electrical connection to the gelled growth medium; when touched to a colony{9} on the plate, the completion of the electrical circuit causes an increment of 1 unit on the readout of the colony counter. (Microbiology)