of the essence or essential element of a thing. / (by extension) Constituting the substance of content rather than its style, and thus always nontrivial.

(grammar) Clipping of noun substantive. / Part of a text that carries the meaning, such as words and their ordering.

(grammar, very rare) to make a word belonging to another part of speech into a substantive (that is, a noun) or use it as a noun

Physical matter; material. / A form of matter that has constant chemical composition and characteristic properties. / The essential part of anything; the most vital part.

(rare, transitive) To give substance to; to make real or substantial.

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.

Auxiliary or supplemental. / Secondary or subordinate. / Of or relating to a subsidy.

A company owned by a parent company or a holding company, also called daughter company or sister company. / (music) A subordinate theme. / One who aids or supplies; an assistant.