The Collaborative International Dictionary of English v.0.48:
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.