substitution
//ˌsʌb.stɪˈtjuː.ʃən//
Noun
substitutionSingular
substitutionsPlural
1
The act of replacing one person or thing with another.
The substitution of butter with margarine made the recipe healthier.
2
A person or thing that takes the place of another.
We need to find a substitution for the broken chair.
3
In sports, the replacement of one player by another during a game.
The coach made a substitution in the second half.
4
In chemistry, a reaction in which one atom or group in a molecule is replaced by another atom or group.
In this substitution reaction, a chlorine atom replaces a hydrogen atom in the molecule.