What does the word spanker mean?

Usage examples for spanker

  1. It was at night, in our watch, and the wind had headed us off a little rather suddenly, and when we had flattened in the jibs, we clewed down the topsails, while the two Benton boys got the spanker sheet aft. – Man Overboard! by F(rancis) Marion Crawford
  2. Shure that's the place where I run me head slap up agin the spanker- boom four days ago. – The Red Eric by R.M. Ballantyne