OPINION OF THE COURT
GIBBONS, Circuit Judge:Derry Finance N.V. (Derry) appeals a partial summary judgment in favor of the Christiana Companies, Inc. (Christiana) in its suit for nonpayment of six recourse promissory notes. (Christiana recourse notes). The district court held that Christiana, the maker of the notes, was relieved from liability by operation of a restrictive provision in those notes. On appeal Derry argues that the district court erred in its holding that the restrictive provision applied, and, in any event, in its rejection of Derry’s equitable estoppel argument. We affirm.
*1212This dispute stems out of a complicated leveraged leaseback transaction. The principal parties to the transaction were Air Florida, Inc. (Air Florida), AIG-737-1, Inc. (AIG), AARK, and Christiana. The transaction, which was proposed by AARK, involved the sale and leaseback of two Boeing 737 aircraft. The deal essentially was structured as follows: Air Florida was to sell the planes to AIG, AIG was then to sell them to AARK, and AARK in turn was to sell them to Christiana. Christiana was then to lease the aircraft back to AIG, which would in turn sublease them to Air Florida.
The various steps in the leaseback transaction were laid out in a series of documents. The basic document was the Participation Agreement. It established the overall structure of the transaction and the obligations of the parties, and incorporated by reference the other documents evidencing it. Chief among these documents for our purposes were: 1) Sales Agreement-I between Air Florida and AIG, 2) Sales Agreement-II between AIG and AARK, 3) the AARK notes by AARK in favor of AIG, 4) Security Agreement-I between AARK, as debtor, and AIG, as secured party, 5) Sales Agreement-Ill between AARK and Christiana, 6) the Christiana recourse notes by Christiana in favor of AARK, 7) Security Agreement-II between Christiana, as debtor, and AARK, as secured party, 8) the Overlease Agreement between Christiana, as lessor, and AIG, as lessee, and 9) the Lease Agreement between AIG, as sublessor, and Air Florida, as sublessee. See Joint Appendix 207-10.
At closing AARK was to purchase the aircraft from AIG by making a cash payment to AIG in the amount of $2,960,000 and by delivering to AIG two nonrecourse installment notes (AARK notes), each in the amount of $10,342,500. Under the terms of the AARK notes, a portion of the cash sum was to represent the first installment on the notes. As security for its obligation, AARK was to execute a security agreement (Security Agreement-I) in favor of AIG. Security Agreement-I gave AIG certain rights upon the occurrence of an “Event of Default” under the AARK notes by reason of certain action or inaction on the part of AARK.
Christiana’s obligations at closing were to purchase the aircraft from AARK and to lease them, pursuant to the Overlease Agreement, to AIG. Christiana was to pay for the planes by delivering to AARK $950,000 in cash, the six Christiana recourse notes, the first two of which were due on July 15, 1981, and a nonrecourse promissory note. The six Christiana recourse notes, which are the subject matter of this appeal, contain the following exculpatory clause:
Payor [Christiana] and Payee [AARK] among others are parties to a certain Participation Agreement ... (“Participation Agreement”). Anything herein to the contrary notwithstanding, payor shall not have any obligation to pay this note nor shall payor have any liability hereunder if, on the maturity date of this note, a default exists under the Participation Agreement or any note, lease, agreement or document contemplated therein, including, without limitation, the Loan Certificates, the Lease and the Overlease (as those terms are defined in the “Participation Agreement.”).
Joint Appendix at 536.
The transaction closed on December 31, 1979. At that time AARK failed to pay the first installment on the notes, which amounted to approximately $600,000. In May of 1981 AARK assigned the Christiana recourse notes to Derry in exchange for a multi-million dollar line of credit. On July 15,1981, the maturity date on the first two Christiana recourse notes, AARK still owed AIG $505,500 out of the $600,000 it failed to pay at closing. In addition, as of July 15, 1981, AIG, as lessee, had failed to make many of the rental payments due Christiana, as lessor, under the Overlease Agreement. In fact from the closing date until February of 1981 AIG made no payments at all. At some point AARK stepped in and paid AIG’s rent from the period running from January 15, 1980 *1213through January 15,1981. No further payments, however, were made until early July 1981. At that time Christiana rejected attempted payments by AARK and AIG. Christiana then refused to make payment on the two recourse notes when they came due. The remaining notes were promptly accelerated.
Derry, the holder of the notes, instituted this suit in federal court on June 28, 1982, seeking to hold Christiana liable on the six notes. On cross-motions for summary judgment, the district court held in favor of Christiana on the ground that AARK’s failure to pay the appropriate cash sum at closing constituted a default within the meaning of the restrictive clause in the Christiana recourse notes thereby relieving Christiana of all liability. See Derry Finance N.V. v. Christiana Companies, Inc., 616 F.Supp. 544 (D.Del.1985).
The pivotal issue on this appeal is the proper interpretation of the exculpatory clause in the Christiana recourse notes stating that Christiana is relieved of liability if “a default exists under” certain.referenced documents. In this case, although they advocate conflicting interpretations of the clause, both Derry and Christiana contend that the clause is unambiguous. Under New York law, which controls this case, the construction of plain and unambiguous language is for the court. See Teitelbaum Holdings, Ltd. v. Gold, 48 N.Y.2d 51, 396 N.E.2d. 1029, 421 N.Y.S.2d 556 (1979); West, Weir & Bartel, Inc. v. Mary Carter Paint Co., 25 N.Y.2d 535, 255 N.E.2d 709, 307 N.Y.S.2d 449 (1969), remittitur amended, 26 N.Y.2d 969, 259 N.E.2d 483, 311 N.Y.S.2d 13 (1970). When the intent of the parties can be gleaned from the documents themselves, the court will not consider extrinsic evidence, but will give effect to the parties’ intent as evidenced by the language they used. See Slatt v. Slatt, 64 N.Y.2d 966, 967, N.E.2d 1099, 488 N.Y.S.2d 645 (1985).
Derry argues, as it did in the distn court, that the unequivocal meaning of th clause is that Christiana is relieved of liability only in the event that a default occurs under the terms of the referenced documents.' In other words, it argues that the parties intended that the referenced documents give meaning and content to the word default; they did not intend for it to have any independent meaning. Applying this rationale, Derry argues that a default did not occur under the AARK notes and Security Agreement-I when AARK failed to pay the first installment on the notes at closing because Security Agreement-I, although not defining when a default per se occurs, states that an “Event of Default” does not occur until three conditions coincide: 1) AARK fails to perform, 2) AIG gives AARK notice of its failure to perform, and 3) a ten-day period elapses after notice is given. Because AIG never gave notice, Derry contends that no default triggering the exculpatory clause occurred. On the other hand, Christiana contends, and the district court found, that the unambiguous meaning of default is its plain meaning, failure to pay or perform, and, thus, that AARK’s nonperformance constituted a default for purposes of the exculpatory clause. We conclude that Derry’s argument is fatally flawed and we decline to follow it.
Several considerations compel us to reject Derry’s argument that the term default incorporates the “Event of Default” provision in Security Agreement-I as the definition of default. First and foremost, the exculpatory clause cannot incorporate anything from Security Agreement-I because the word default is simply not defined in that document. Security Agreement-I and the other referenced documents speak in terms of “Events of Default,” not “default.”1 Thus, Security Agreement-I
*1214or grants AIG, the party owed the percance, rights upon the occurrence of an /ent of Default.” “Event of Default” is acifically defined in Security Agreeent-I as the
failure of Debtor [AARK] promptly and faithfully to pay, observe and perform when due any of the Obligations [defined as making payments under the AARK note] ... and such failure shall continue for a period of ten (10) days after written notice thereof.
Joint Appendix at 516. As a comparison of these documents illustrates, there is nothing in either Security Agreement-I nor the Christiana recourse notes that leads to the conclusion that “default” is the equivalent of “Event of Default.”
The obvious distinction between these terms is borne out by the fact that the word “default” in the exculpatory clause is in lower case letters whereas the term “Event of Default”, which is clearly a term of art, is always capitalized. Upon a review of ail the referenced documents, it becomes clear that when the parties intended to create a term of art or to incorporate specific definitions from other documents, they capitalized the referencing term and then utilized the same term in the referenced document. An example of this can be found in the relationship between Sales Agreement-II between AIG and AARK and the Lease Agreement between AIG and Air Florida. Sales Agreement-II grants AARK certain rights upon the occurrence of an “Event of Default” under the Lease. The Lease, the referenced document, specifically defines “Event of Default” using the term “Event of Default.” The incorporation could not be clearer.
The difference between the meaning of the lower case “default” and the capitalized “Event of Default” is perhaps best illustrated by a provision in the Overlease Agreement between Christiana and AIG in which the parties use both terms and they obviously ascribe different meanings to them. The provision, which defines what constitutes an “Event of Default” for purposes of that agreement, states that an “Event of Default” occurs if “AIG shall default in the payment of any installment of Rent as and when the same becomes due and payable, and such default shall continue for a period of ten (10) days after written notice.” Joint Appendix at 854-55 (emphasis supplied). Clearly, in this provision, the parties intended for the word default, which is written in lower case letters as it is in the exculpatory clause, to have its ordinary, plain meaning.
Finally, an examination of the purposes served by the two terms further convinces us that they are not functional equivalents and therefore that one does not incorporate the other. Under the exculpatory clause, a “default” enables Christiana to avoid liability on the recourse notes; however, under the “Event of Default” clauses in the other documents, the occurrence of an “Event of Default” automatically triggers in the party owed performance all of the rights afforded secured parties under the Uniform Commercial Code, including the right to take possession of the aircraft.2 Thus the “Event of Default” clause gives the obligee access to equity; the default clause does not.
For the above reasons, we conclude that Derry’s reading of the restrictive provision is not supported by the language of the documents. Derry’s construction leads only to hopeless confusion since there is no such thing as a “default” within the meaning of Security Agreement-I and the AARK notes. A “default” is simply not the same thing as an “Event of Default.” Therefore there can be no incorporation. The intention of the parties is plain on the face of the documents: The word default means failure to perform.
Derry contends, however, that even if default is given its plain meaning, no default occurred for purposes of the excul*1215patory clause because AARK and AIG entered into a separate, oral agreement deferring AARK’s obligation under the AARK notes to pay the first installment until some, time after closing when AARK could discount the Christiana notes. The district court rejected this argument and we do too. When drafted, Christiana and AARK agreed that Christiana would be relieved of liability on the notes if, inter alia, AARK failed to perform its obligation to pay a certain cash sum to AIG at closing. This agreement cannot be modified or changed without the consent of Christiana. See, e.g., Beacon Terminal Corp. v. Chemprene, Inc., 75 A.D.2d 350, 429 N.Y.S.2d 715 (N.Y.App.Div.1980) (modification requires mutual assent); Lundberg v. Board of Education of Gloversville Enlarged School District, 127 Misc.2d 804, 487 N.Y.S.2d 306 (N.Y.Sup.Ct.1985) (unilateral modification not binding on other party). Derry points to no agreement, written or oral, to which Christiana was a party that modifies the Christiana notes. Therefore the plain meaning of the notes controls, and AIG’s and AARK’s alleged oral modification has no bearing on Christiana’s rights under the exculpatory clause in the recourse notes.
Finally, Derry contends that in any event Christiana is liable on the notes because Christiana is estopped from raising the exculpatory clause as a defense.3 Derry’s estoppel argument is based on a conversation that a Mr. D.W.H. McCowan, one of the principals of Derry, had with a Mr. George Weymouth, who was a close personal friend of Mr. Martin Fenton, the president of Christiana. The conversation took place before Derry purchased the notes. McCowan asked Weymouth whether it was his understanding that Christiana would pay the notes when due. Weymouth spoke with Fenton and Fenton assured Weymouth that Christiana intended to pay them. At the time Fenton made this representation to Weymouth, Fenton was aware that Weymouth was inquiring on behalf of someone in Bermuda who was interested in purchasing the notes and on his own family’s behalf, which was considering the purchase of a participation in the notes. Weymouth conveyed Fenton’s response to McCowan. McCowan resides in Bermuda.
The district court concluded, after draw-' ing all reasonable inferences in Derry’s favor, that Derry failed to satisfy the elements necessary for the application of the equitable estoppel doctrine. We agree with the conclusion of the district court. Derry has not produced any evidence from which one could reasonably infer that Fen-ton intended or even imagined that a prospective purchaser of these notes would, without further inquiry, rely on this telephone conversation as Christiana’s final and fixed intention. Moreover, Derry’s estoppel argument requires it to show that its reliance on Fenton’s statement, reported to McCowen secondhand by Weymouth, was reasonable. However, Derry has produced nothing to justify its dependence upon these remarks made by Fenton, upon a relatively informal inquiry, regarding future plans of Christiana towards obligations that had not yet matured. For these reasons, Derry’s estoppel argument cannot succeed.
We hold that AARK’s failure to pay the requisite cash sum to AIG at the December 1979 closing triggered the exculpatory clause in the Christiana recourse notes relieving Christiana of all liability because AARK’s nonperformance constituted a default within the meaning of that clause. In addition we hold that Christiana is not es-topped from raising the exculpatory clause as a defense to this suit for nonpayment. The summary judgment will therefore be affirmed.
. The "Event of Default" provision in Security Agreement-I is captioned "Default”, but we must disregard the caption because another section of the Agreement states that the captions are meaningless. In addition, another document in the transaction, which is unrelated to this appeal, grants the secured party rights upon the occurrence of a "Default” and specifically defines “Default," not "default.” See Joint Appendix at 276-85 (Security Agreement between First *1214National Bank of Dallas and AIG). It is clear in this document that "Default,” unlike "default,” is a term of art.
. Subject, of course, to any prior security interests.
. Derry does not argue on appeal, as it did in the district court, that Christiana waived its rights under the exculpatory clause.