Source : Webster's Revised Unabridged Dictionary (1913)

Hagdon \Hag"don\, n. (Zo["o]l.)
   One of several species of sea birds of the genus {Puffinus};
   esp., {P. major}, the greater shearwarter, and {P.
   Stricklandi}, the black hagdon or sooty shearwater; -- called
   also {hagdown}, {haglin}, and {hag}. See {Shearwater}.