(philosophy) A logical relationship in which two terms can be mutually substituted without affecting the truth value of any propositions in which the terms occur, thereby establishing that the terms are identical.

The act of substituting or the state of being substituted. / A substitute or replacement.

(transitive) To use in place of something else, with the same function. / (transitive, in the phrase "substitute X for Y") To use X in place of Y.

A replacement or stand-in for something that achieves a similar result or purpose. / (sports) A player who is available to replace another if the need arises, and who may or may not actually do so.

Capable of being used as a substitute; valid as a replacement or alternate item. / Capable of being substituted.

Something that can be substituted for something else; a viable replacement.

simple past tense and past participle of substitute

present participle of substitute

plural of substitute

Third-person singular simple present indicative form of substitute