bolster

American  

[bohl-ster] / ˈboʊl stər /

noun

1. a long, often cylindrical, cushion or pillow for a bed, sofa, etc.

2. anything resembling this in form or in use as a support.

3. any pillow, cushion, or pad.

4. Nautical.

   1. Also called bolster plate.  a circular casting on the side of a vessel, through which an anchor chain passes.

   2. a timber used as a temporary support.

   3. a beam for holding lines or rigging without chafing.

   4. a bag filled with buoyant material, fitted into a small boat.

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

6. Masonry.

   1. a timber or the like connecting two ribs of a centering.

   2. a chisel with a blade splayed toward the edge, used for cutting bricks.

7. Carpentry. a horizontal timber on a post for lessening the free span of a beam.

8. a structural member on which one end of a bridge truss rests.

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verb (used with object)

1. to support with or as with a pillow or cushion.

2. to add to, support, strengthen, or uphold (sometimes followed byup ).

   They bolstered their morale by singing.

   He bolstered up his claim with new evidence.

   Synonyms:

   fortify, reinforce, aid, sustain, strengthen

bolster British  

/ ˈbəʊlstə /

verb

1. (often foll by up) to support or reinforce; strengthen

   to bolster morale

2. to prop up with a pillow or cushion

3. to add padding to

   to bolster a dress

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noun

1. a long narrow pillow or cushion

2. any pad or padded support

3. 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

4. a cold chisel having a broad blade splayed towards the cutting edge, used for cutting stone slabs, etc

Related Words

See cushion.

Other Word Forms

• bolsterer noun
• bolstering noun
• unbolster verb (used with object)

Etymology

Origin of bolster

First recorded before 1000; Middle English bolstre (noun), Old English bolster; cognate with Old Norse bolstr, Dutch bolster, German Polster

Example Sentences

Volunteer firefighters like Maitree Nuanja do their best to bolster limited local capacity, relying heavily on donations such as drinking water and face masks.

From Barron's • Apr. 3, 2026

This new crisis will again strengthen the resolve of European countries and Canada to bolster their own defences and depend on themselves for their own security.

From BBC • Apr. 1, 2026

Also last month, Mistral AI clinched its first acquisition with the purchase of infrastructure startup Koyeb as it seeks to bolster computing capabilities.

From The Wall Street Journal • Mar. 30, 2026

He has even launched his own foundation, a Panama-based entity from which he hopes to offer a “rejuvenation cocktail,” a gene therapy that boosts follistatin, klotho, and SIRT1, another protein said to bolster longevity.

From Slate • Mar. 30, 2026

I think about the old woman from our block, Khadijah auntie, who raised her fist to bolster me when some of the others were yelling at me about the fast.

From "Internment" by Samira Ahmed

Related Words

• aid
• boost
• buoy
• buttress
• cushion
• help
• maintain
• reinforce
• shore up
• strengthen
• support
• sustain