From The Collaborative International Dictionary of English v.0.48 [gcide]:
Banister \Ban"is*ter\, n. [A corruption of baluster.]
1. A baluster.
[1913 Webster]
2. (sing. or pl.) The balustrade of a staircase. Formerly
used in this sense mostly in the plural, now mostly in the
singular. [Also spelled bannister.]
[1913 Webster +PJC]
He struggled to ascend the pulpit stairs, holding
hard on the banisters. --Sir W.
Scott.
From The Collaborative International Dictionary of English v.0.48 [gcide]:
bannister \bannister\ n.
same as banister.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) [wn]:
Bannister
n 1: English runner who in 1954 became the first person to run a
mile in less than four minutes (born in 1929) [syn:
Bannister, Roger Bannister, {Sir Roger Gilbert
Bannister}]
2: a railing at the side of a staircase or balcony to prevent
people from falling [syn: bannister, banister,
balustrade, balusters, handrail]