topmast

/ˈtɑpˌmæst/
noun
  1. The second section of a ship's mast, above the lower mast and below the topgallant mast.
    • During the storm, the topmast snapped under the strong wind.
    • The ship's topmast was painted white to stand out against the sky.
    • The sailor climbed the topmast to adjust the sails.