Source : Webster's Revised Unabridged Dictionary (1913)

Harvestman \Har"vest*man\, n.; pl. {Harvestmen}.
   1. A man engaged in harvesting. --Shak.

   2. (Zo["o]l.) See {Daddy longlegs}, 1.

Source : WordNet®

harvestman
     n : spider-like arachnid with a small rounded body and very long
         thin legs [syn: {daddy longlegs}, {Phalangium opilio}]