From The Collaborative International Dictionary of English v.0.48 [gcide]:
Sideboard \Side"board`\, n.
A piece of dining-room furniture having compartments and
shelves for keeping or displaying articles of table service.
[1913 Webster]
At a stately sideboard, by the wine,
That fragrant smell diffused. --Milton.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
sideboard
n 1: a removable board fitted on the side of a wagon to increase
its capacity
2: a board that forms part of the side of a bed or crib
3: a piece of furniture that stands at the side of a dining
room; has shelves and drawers [syn: buffet, counter,
sideboard]