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.

---

verb (used with object)

bolsters, present (3rd person singular) bolstered, past participle, past bolstering present participle

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

---

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

Synonym Usage

See cushion.

Other Word Forms

Derived Forms

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

Conjugated Forms

Present

• has bolstered
  perfect 3rd person singular
• have bolstered
  perfect
• are bolstering
  progressive
• bolstering
  participle
• have been bolstering
  perfect progressive
• has been bolstering
  perfect progressive 3rd person singular
• bolsters
  singular 3rd person
• am bolstering
  progressive 1st person singular
• is bolstering
  progressive 3rd person singular

Past

• had bolstered
  perfect
• bolstered
  participle
• bolstered
  simple
• was bolstering
  progressive singular
• had been bolstering
  perfect progressive
• were bolstering
  progressive plural

Future

• will bolster
  simple
• will have bolstered
  perfect
• will have been bolstering
  perfect progressive
• will be bolstering
  progressive

Etymology

Origin of bolster

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

Explanation

When you cheer up a friend who's feeling down, you bolster them. To bolster is to offer support or strengthen. A bolster is also the name of a long pillow you might use to make your back feel better. And the two uses are not dissimilar. When you bolster your friends, you support them and prop them up, just like the pillow does for your back. When you're trying to bolster your credibility, you find people and/or documents that support you or your view. Bolster efforts to learn this word!

Example Sentences

Vaughan asked her if she had meant two voices would bolster the case.

From BBC • Jun. 3, 2026

Documenting such occurrences can bolster your allegation of ageism.

From MarketWatch • Jun. 3, 2026

The rapidly evolving military technology needed to create new weapon systems requires research-and-development projects that can bolster the domestic economy.

From The Wall Street Journal • Jun. 1, 2026

The move will bolster an already formidable Rams pass rushing unit that has played a integral part in the Rams being among the favorites to win the Super Bowl at SoFi Stadium in February.

From Los Angeles Times • Jun. 1, 2026

And to bolster his case: “He’s a subscriber.”

From "Middlesex: A Novel" by Jeffrey Eugenides

Related Words

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