Source : Webster's Revised Unabridged Dictionary (1913)

Boarder \Board"er\, n.
   1. One who has food statedly at another's table, or meals and
      lodgings in his house, for pay, or compensation of any
      kind.

   2. (Naut.) One who boards a ship; one selected to board an
      enemy's ship. --Totten.

Source : WordNet®

boarder
     n 1: a tenant in someone's house [syn: {lodger}, {roomer}]
     2: someone who forces their way aboard ship; "stand by to repel
        boarders"
     3: a pupil who lives at school during term time