a person or thing acting or serving in place of another.
(formerly) a person who, for payment, served in an army or navy in the place of a conscript.
Grammar. a word that functions as a replacement for any member of a class of words or constructions, as do in He doesn’t know but I do.
verb (used with object), substituted, substituting.
to put (a person or thing) in the place of another.
to take the place of; replace.
Chemistry. to replace (one or more elements or groups in a compound) by other elements or groups.
verb (used without object), substituted, substituting.
to act as a substitute.
of or relating to a substitute or substitutes.
composed of substitutes.
(often foll by for) to serve or cause to serve in place of another person or thing
(chem) to replace (an atom or group in a molecule) with (another atom or group)
(logic, maths) to replace (one expression) by (another) in the context of a third, as replacing x + y for x in 3x = k gives 3x + 3y = k
a person or thing that serves in place of another, such as a player in a game who takes the place of an injured colleague
(as modifier): a substitute goalkeeper Often shortened to sub
(grammar) another name for pro-form
(Canadian) another name for supply teacher
(nautical) another word for repeater (sense 5)
(formerly) a person paid to replace another due for military service
noun, Cryptography. 1. a cipher that replaces letters of the plain text with another set of letters or symbols.
- Substitution product
substitution product n. A product obtained by replacing one atom or group in a molecule with another atom or group.
noun, Chemistry. 1. the replacement of an atom or group of atoms in a compound by another atom or group.
- Substitution therapy
substitution therapy n. Replacement therapy in which a substitute substance is used.