The Collaborative International Dictionary of English v.0.48:

Seg \Seg\, n. [See Sedge.] (Bot.)
   1. Sedge. [Obs.]
      [1913 Webster]

   2. The gladen, and other species of Iris. --Prior.
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The Collaborative International Dictionary of English v.0.48:

Seg \Seg\, n. [Probably from the root of L. secare to cut.]
   A castrated bull. [Prov. Eng. & Scot.] --Halliwell.
   [1913 Webster]