#buoy  bright-colored; a float attached by rope to the seabed to mark channels in a harbor or underwater hazards
  supertype:  reference_point__referencepoint__point_of_reference__reference  an indicator that orients you generally; "it is used as a reference for comparing the heating and the electrical energy involved"
  subtype:  acoustic_buoy  a buoy that can be heard (at night)
     subtype:  bell_buoy__gong_buoy  a buoy with a bell on it
     subtype:  whistle_buoy__whistlebuoy__whistlingbuoy  a buoy that makes a whistling noise
  subtype:  can_buoy__canbuoy__can  a buoy with a round bottom and conical top
  subtype:  conical_buoy__conicalbuoy__nun__nunbuoy  a buoy resembling a cone
  subtype:  spar_buoy  a buoy resembling a vertical log

No statement uses or specializes buoy; click here to add one.