Substitution - Definition and Overview

In general, substitution is the replacement of one thing with another. There are many specific examples:

• In organic chemistry, a reaction where one functional group takes the place of another. A major type of substitution is nucleophilic substitution.
• The substitution cipher in cryptography.
• The substitution rule in calculus.
• Import substitution in trade.
• Substitute good in consumer theory.
• The substitution method in the testing of optical fiber.
• The substitution property of equality in mathematics.
• Chord substitution in music.