Definition of: substitute

(sub′stə·tt, -tyt) v. ·tut·ed, ·tut·ing v.t.
1. To put in the place of another person or thing.
2. To take the place of.
—v.i.
3. To act as a substitute.
4. Chem. To exchange one constituent of a compound for, or replace it with, another. See synonyms under CHANGE.
—noun
1. One who or that which takes the place or serves in lieu of another.
2. In the American Civil War, one hired to serve in the place of a man drafted into military service.
3. Any substance or material adapted to replace another in a given product or process, or for a specified purpose: Gelatin is a substitute for agar, synthetic rubber for cork, etc.: also called alternative, replacement. See synonyms under DELEGATE. [<L substitutus, pp. of substituere <sub- in place of + statuere set up]