Definition of: bolster

(bōl′stər) noun
1. A long, narrow pillow as wide as a bed.
2. A pad used as a support or for protection.
3. Anything shaped like or used as a bolster.
4. Archit. a The lateral part of the volute of an Ionic capital, b A crosspiece of an arch centering, running from rib to rib and bearing the voussoirs.
5. Mech. A steel block which supports the die in a punching machine.
—v.t.
1. To support with a pillow.
2. To prop up, as something ready to fall: with up.
3. To furnish with padding. [OE]
—bol′ster·er noun