The Collaborative International Dictionary of English v.0.48:

handrail \hand"rail`\ n.
   a rail[1] at the side of staircase or balcony to prevent
   people from falling; -- shaped so as to be conveniently
   gripped with the hand; as, please hold onto the handrail when
   crossing the walkway.

   Syn: bannister, banister, balustrade, balusters.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

handrail
    n 1: a railing at the side of a staircase or balcony to prevent
         people from falling [syn: bannister, banister,
         balustrade, balusters, handrail]