The terms of the agreement are unambiguous. Thus, resort to extrinsic evidence is inadmissible to vary the writing (see W.W.W. *574Assoc. v Giancontieri, 77 NY2d 157, 162 [1990]). The fact that the “Purchase Contract” had not yet been drafted does not alter our determination, since the agreement contemplates the execution of a “Purchase Contract” at some future date. We reject defendants’ contention that “Purchase Contract” means anything other than that accorded to the term in ordinary usage; or that “Purchase Contract” is a distinct term of art rendering the document ambiguous. As the past consideration is “expressed in the writing” and was “proved to have been given or performed,” the contractual obligation is valid (General Obligations Law § 5-1105).
We have considered defendants’ remaining arguments and find them unavailing. Concur — Mazzarelli, J.P., Andrias, Catterson, Moskowitz and Román, JJ.