retarder

American  

[ri-tahr-der] / rɪˈtɑr dər /

noun

1. a person or thing that retards.

2. Chemistry.

   1. any substance added to rubber to delay or prevent vulcanization.

   2. any substance added to delay a process.

3. Building Trades. an admixture of concrete or plaster that retards its set.

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retarder British  

/ rɪˈtɑːdə /

noun

1. a person or thing that retards

2. a substance added to slow down the rate of a chemical change, such as one added to cement to delay its setting

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Etymology

Origin of retarder

First recorded in 1635–45; retard + -er ¹

Example Sentences

They must also utilize a Class 1 vapor retarder with joints overlapping 6 inches, that extends up the stem wall and that is sealed from the exterior.

From Seattle Times • Aug. 25, 2022

The inquest jury heard the French report concluded the brake failed as the pad had been "completely destroyed by excessive heating" due to the "poor condition of the hydraulic retarder".

From BBC • Nov. 22, 2017

In raw form its principal use is as a retarder in cement, preventing it from setting too rapidly.

From Time Magazine Archive

Citric acid is the retarder in this case.

From Scientific American Supplement, No. 288, July 9, 1881 by Various

Guess O King, what that was:—Exhauster of men, retarder of words, yet originator of speech.

From Stories and Ballads of the Far Past Translated from the Norse (Icelandic and Faroese) with Introductions and Notes by Kershaw, Nora