Meaning of equi NP deletion

equi NP deletion

Pronunciation: [key]
— Ling. Ling.
  1. a rule of transformational grammar that deletes the underlying subject of a complement clause if it is coreferential with the subject or object of the main clause, as in John promised to return the money, where the underlying subject (John) of return has been deleted. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.