#topmast  the mast next above a lower mast and topmost in a fore-and-aft rig
  supertype:  mast  a vertical spar for supporting sails
  subtype:  fore-topmast  the topmast next above the foremast
  subtype:  main-topmast  the topmast next above the mainmast
  subtype:  royal_mast__royalmast  topmast immediately above the topgallant mast
  subtype:  topgallant_mast__topgallant  a mast fixed to the head of a topmast on a square-rigged vessel

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