DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   CRO \CRO\ n. (Electronics)
      acronym for cathode-ray oscilloscope, an electronic device
      which provides visual images of varying electrical
      quantities. See oscilloscope.
      Syn: oscilloscope, scope, cathode-ray oscilloscope.
           [WordNet 1.5]