Bolster

a long, often cylindrical, cushion or pillow for a bed, sofa, etc.
anything resembling this in form or in use as a support.
any pillow, cushion, or pad.
Nautical.

Also called bolster plate. a circular casting on the side of a vessel, through which an anchor chain passes.
a timber used as a temporary support.
a beam for holding lines or rigging without chafing.
a bag filled with buoyant material, fitted into a small boat.

Metalworking. an anvillike support for the lower die of a drop forge.
Masonry.

a timber or the like connecting two ribs of a centering.
a chisel with a blade splayed toward the edge, used for cutting bricks.

Carpentry. a horizontal timber on a post for lessening the free span of a beam.
a structural member on which one end of a bridge truss rests.
to support with or as with a pillow or cushion.
to add to, support, or uphold (sometimes followed by up):
They bolstered their morale by singing. He bolstered up his claim with new evidence.
Contemporary Examples

The Aftermath of Disney’s ‘Million Dollar Arm’ Alex Suskind May 15, 2014
Human-Rights Toll of U.S. Shooting in Afghanistan Heather Barr March 14, 2012
When Will We Get Our Money Back? Nomi Prins March 1, 2010
‘Ghostbusters’ and the Slow Emancipation of Female-Driven Comedy Teo Bugbee August 14, 2014
6 Wackiest Osama bin Laden Conspiracy Theories Josh Dzieza May 8, 2011

Historical Examples

Henry Dunbar M. E. Braddon
Astounding Stories of Super-Science, November, 1930 Various
The Man in the Twilight Ridgwell Cullum
Rollo on the Atlantic Jacob Abbott
Gatherings From Spain Richard Ford

verb (transitive)
(often foll by up) to support or reinforce; strengthen: to bolster morale
to prop up with a pillow or cushion
to add padding to: to bolster a dress
noun
a long narrow pillow or cushion
any pad or padded support
(architect) a short horizontal length of timber fixed to the top of a post to increase the bearing area and reduce the span of the supported beam
a cold chisel having a broad blade splayed towards the cutting edge, used for cutting stone slabs, etc
n.
v.