substitution

British  

/ ˌsʌbstɪˈtjuːʃən /

noun

1. the act of substituting or state of being substituted

2. something or someone substituted

3. maths the replacement of a term of an equation by another that is known to have the same value in order to simplify the equation

4. maths logic

   1. the uniform replacement of one expression by another

   2. an expression so derived from another

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Explanation

The noun substitution refers to the act of replacing one thing with another. Your football coach might make a substitution by sending you onto the field to take over for a player who is tired or injured. Substitution comes from the Middle French word of the same spelling, meaning "a putting in place of another." You might notice that substitution contains the root word substitute, and that's a good way to remember the meaning of the word. In school, a substitute is a temporary teacher who fills in when your regular teacher is out — in other words, a substitution has been made until your teacher returns.

Example Sentences

See Examples For:

substitution

The Galaxy’s first substitution came in the 68th minute, when Lozano left the field to make way for Robert Taylor.

From Los Angeles Times ● Aug. 20, 2026

The substitution models suggested that replacing one daily serving of a sugary beverage with whole fruit could be associated with a 22% lower risk of developing high blood pressure.

From Science Daily ● Jul. 23, 2026

Weintraub also describes the security context in Colombia as "fragile" - making it difficult for substitution programmes to operate effectively in many rural areas.

From BBC ● Jul. 19, 2026

The company is working to mitigate costs through product substitution, supply chain actions and customer contract renegotiations.

From The Wall Street Journal ● Jul. 15, 2026

In a substitution cipher, each letter of the message you want to send is swapped out for a different letter.

From "The Woman All Spies Fear" by Amy Butler Greenfield