In linguistics, transformational grammar or transformational-generative grammar is part of the theory of generative grammar, especially of natural languages. Wikipedia

A generative grammar developed in the Chomskyan tradition Wikipedia Disambiguation

A generative grammar, especially of a natural language, developed in the Chomskyan tradition of phrase structure grammars (as opposed to dependency grammars), and involving the use of defined operations called transformations to produce new sentences from existing ones. Wiktionary