Source : Webster's Revised Unabridged Dictionary (1913)

Right-hand \Right"-hand`\, a.
   1. Situated or being on the right; nearer the right hand than
      the left; as, the right-hand side, room, or road.

   2. Chiefly relied on; almost indispensable.

            Mr. Alexander Truncheon, who is their right-hand man
            in the troop.                         --Addison.

   {Right-hand rope}, a rope which is laid up and twisted with
      the sun, that is, in the same direction as plain-laid
      rope. See Illust. of {Cordage}.

Source : WordNet®

right-hand
     adj 1: located on or directed toward the right; "a right-hand turn"
            [syn: {right-hand(a)}]
     2: intended for the right hand; "a right-hand glove" [syn: {right(a)},
         {right-hand(a)}]
     3: most helpful and reliable; "my right-hand man"