| Definition -
A Chomskyan term denoting the underlying syntactic structures that make up the universal grammar.
For example, the sentences Pat loves Chris and Chris is loved by Pat mean roughly the same thing. Chomsky accounts for this similarity by positing that these two sentences are distinct surface structure forms derived via transformations from a common deep structure item.
1. The role and significance of deep structure has changed substantially since Chomsky first formulated his theories; in fact, since the 1990s the deep structure concept has become irrelevant to his current theories.