INDENTURE SUPPLEMENT

Exhibit 4.1

EXECUTION VERSION

DISCOVER CARD EXECUTION NOTE TRUST

Issuer

and

U.S. BANK NATIONAL ASSOCIATION

Indenture Trustee

CLASS A(2008-C) TERMS DOCUMENT

Dated as of August 28, 2008

to

INDENTURE SUPPLEMENT

Dated as of July 26, 2007

for the DiscoverSeries Notes

to

INDENTURE

Dated as of July 26, 2007

TABLE OF CONTENTS

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THIS CLASS A(2008-C) TERMS DOCUMENT (this “ Terms Document ”), by and between DISCOVER CARD EXECUTION NOTE TRUST, a statutory trust created under the laws of the State of Delaware (the “ Issuer ”), and U.S. BANK NATIONAL ASSOCIATION, a national banking association organized and existing under the laws of the United States of America, as Indenture Trustee (the “ Indenture Trustee ”), is made and entered into as of August 28, 2008.

Pursuant to this Terms Document, the Issuer shall create a new Tranche of Class A Notes of the DiscoverSeries and shall specify the principal terms thereof.

ARTICLE I

Definitions and Other Provisions of General Application

Section 1.01. Definitions . For all purposes of this Terms Document, except as otherwise expressly provided or unless the context otherwise requires:

(1) the terms defined in this Article have the meanings assigned to them in this Article, and include the plural as well as the singular;

(2) all other terms used herein which are defined in the Note Purchase Agreement dated as of August 28, 2008, by and among Discover Card Execution Note Trust, Discover Bank, Salisbury Receivables Company LLC and Sheffield Receivables Corporation, as purchasers, Barclays Bank PLC, as committed purchaser and agent (as may be amended, supplemented, restated, amended and restated or otherwise modified from time to time, the “ Note Purchase Agreement ”), the Indenture Supplement or the Indenture, either directly or by reference therein, have the meanings assigned to them therein;

(3) all accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles and, except as otherwise herein expressly provided, the term “generally accepted accounting principles” with respect to any computation required or permitted hereunder means such accounting principles as are generally accepted in the United States of America at the date of such computation;

(4) all references in this Terms Document to designated “Articles,” “Sections” and other subdivisions are to the designated Articles, Sections and other subdivisions of this Terms Document; the words “herein,” “hereof” and “hereunder” and other words of similar import refer to this Terms Document as a whole and not to any particular Article, Section or other subdivision;

(5) in the event that any term or provision contained herein shall conflict with or be inconsistent with any term or provision contained in the Indenture Supplement or the Indenture, the terms and provisions of this Terms Document shall be controlling, but solely with respect to the Class A(2008-C) Notes;

(6) each capitalized term defined herein shall relate only to the Class A(2008-C) Notes and no other Tranche of Notes issued by the Issuer;

(7) “including” and words of similar import will be deemed to be followed by “without limitation”; and

(8) for purposes of determining any amount or making any calculation hereunder, such amount or calculation, (x) if specified to be as of the first day of any Due Period, shall (a) include any Notes issued during such Due Period as if such Notes had been outstanding on the first day of such Due Period and (b) give effect to any payments, deposits or other allocations made on the Distribution Date related to the prior Due Period, and (y) if specified to be as of the close of business on the last day of any Due Period shall give effect to any payments, deposits or other allocations made on the related Distribution Date.

“ Agent ” has the meaning set forth in the Note Purchase Agreement.

“ Class A(2008-C) Adverse Event ” means the occurrence of any of the following: (a) an Early Redemption Event with respect to the Class A(2008-C) Notes or (b) an Event of Default and acceleration of the Class A(2008-C) Notes; provided , however , that if the only such event to have occurred is an Excess Spread Early Redemption Event for which an Excess Spread Early Redemption Cure has occurred, a Class A(2008-C) Adverse Event shall not be treated as continuing from and after the date of such cure.

“ Class A(2008-C) Note ” means any Note, in the form set forth in Exhibit A hereto, designated therein as a Class A(2008-C) Note and duly executed and authenticated in accordance with the Indenture.

“ Class A(2008-C) Noteholder ” means a Person in whose name a Class A(2008-C) Note is registered in the Note Register.

“ Class A(2008-C) Termination Date ” means the earliest to occur of (a) the Principal Payment Date on which the Outstanding Dollar Principal Amount of the Class A(2008-C) Notes is paid in full, (b) the Legal Maturity Date and (c) the date on which the Indenture is discharged and satisfied pursuant to Article VI thereof.

“ Class A(2008-C) Tranche Interest Allocation ” for the Class A(2008-C) Notes for any Distribution Date means the Note Interest for the Class A(2008-C) Notes.

“ Consent Date ” has the meaning set forth in the Note Purchase Agreement.

“ Excess Spread Percentage ” for any Distribution Date means a fraction, the numerator of which is the Excess Spread Amount for such Distribution Date multiplied by 12 and the denominator of which is the sum of the Nominal Liquidation Amounts of all Tranches of DiscoverSeries Notes as of the first day of the related Due Period.

“ Existing Expected Maturity Date ” has the meaning set forth in the Note Purchase Agreement.

“ Existing Legal Maturity Date ” has the meaning set forth in the Note Purchase Agreement.

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“ Existing Liquidation Commencement Date ” has the meaning set forth in the Note Purchase Agreement.

“ Existing Termination Date ” has the meaning set forth in the Note Purchase Agreement.

“ Expected Maturity Date ” means August 17, 2009 or, if such date is extended pursuant to the Note Purchase Agreement, the Existing Expected Maturity Date.

“ Expected Principal Payment Date ” means each Distribution Date commencing on the earliest to occur of (i) the Distribution Date next succeeding the failure of the parties to the Note Purchase Agreement to extend any Existing Termination Date on or prior to the applicable Consent Date pursuant to Section 2.10 of the Note Purchase Agreement and (ii) the Expected Maturity Date.

“ Increased Costs Amount ” has the meaning set forth in the Note Purchase Agreement.

“ Indenture ” means the Indenture dated as of July 26, 2007 between the Issuer and Indenture Trustee, as the same may be amended, supplemented, restated, amended and restated, replaced or otherwise modified from time to time.

“ Indenture Supplement ” means the Indenture Supplement dated as of July 26, 2007 for the DiscoverSeries Notes, by and between the Issuer and the Indenture Trustee, as the same may be amended, supplemented, restated, amended and restated, replaced or otherwise modified from time to time.

“ Initial Dollar Principal Amount ” means $0, or such higher amount as is specified in any Notice of Additional Issuance under Section 2.09.

“ Interest Accrual Period ” means, with respect to any Interest Payment Date, the period from and including the previous Interest Payment Date (or, in the case of the first Interest Payment Date for any Class A(2008-C) Note, from and including the applicable Issuance Date) to but excluding such Interest Payment Date.

“ Interest Payment Date ” means the fifteenth day of each month commencing in September 2008, or if such fifteenth day is not a Business Day, the next succeeding Business Day.

“ Issuance Date ” means August 28, 2008, with respect to all Class A(2008-C) Notes issued on the date hereof and, with respect to any increase in the Outstanding Dollar Principal Amount pursuant to Section 2.09, any Issuance Date specified in the Notice of Additional Issuance delivered thereunder.

“ Legal Maturity Date ” means February 15, 2012 or, if such date is extended pursuant to the Note Purchase Agreement, the Existing Legal Maturity Date.

“ Liquidation Amount ” means the Nominal Liquidation Amount of the Class A(2008-C) Notes.

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“ Liquidation Commencement Date ” means the date that is the earliest to occur of (i) the Distribution Date next succeeding the failure of the parties to the Note Purchase Agreement to extend any Existing Termination Date (whether by notice or by the failure to deliver notice on or prior to the applicable Consent Date) pursuant to Section 2.10 of the Note Purchase Agreement and (ii) the Existing Liquidation Commencement Date.

“ Liquidation Period ” for these Class A(2008-C) Notes means, unless an Early Redemption Event or an Event of Default for these Class A(2008-C) Notes shall have occurred prior thereto, the period commencing on the Liquidation Commencement Date and ending on the earlier to occur of (x) the payment in full of the Outstanding Dollar Principal Amount of these Class A(2008-C) Notes or (y) the occurrence of an Early Redemption Event or an Event of Default for these Class A(2008-C) Notes; provided , however , that if an Excess Spread Early Redemption Cure has occurred with respect to any Excess Spread Early Redemption Event for these Class A(2008-C) Notes prior to the commencement of the Liquidation Period for these Class A(2008-C) Notes (and no other Early Redemption Event or Event of Default for these Class A(2008-C) Notes has occurred), the Liquidation Period for these Class A(2008-C) Notes shall be determined as if such Excess Spread Early Redemption Event had not occurred, and if the Liquidation Period has terminated in accordance with clause (y), the Liquidation Period for these Class A(2008-C) Notes shall resume and shall continue until the earlier to occur of (x) the payment in full of the Outstanding Dollar Principal Amount of these Class A(2008-C) Notes or (y) the occurrence of a subsequent Early Redemption Event or Event of Default.

“ Note Interest ” for these Class A(2008-C) Notes has the meaning set forth in the Note Purchase Agreement.

“ Note Interest Rate ” for these Class A(2008-C) Notes has the meaning set forth in the Note Purchase Agreement; for the avoidance of doubt the Note Interest Rate shall be calculated in accordance with the calculation basis set forth in the Note Purchase Agreement.

“ Notice of Additional Issuance ” has the meaning set forth in Section 2.09.

“ Principal Payment Date ” means, for the Class A(2008-C) Notes, each Expected Principal Payment Date, or upon the acceleration of such Notes following an Event of Default or upon the occurrence and during the continuance of an Early Redemption Event (unless all such events have been cured), each Distribution Date and the Legal Maturity Date, or in the event of a cleanup call, the date of redemption in accordance with Section 1202 of the Indenture.

“ Required Daily Deposit Target Finance Charge Amount ” means, for any day in a Due Period, an amount equal to the Class A(2008-C) Tranche Interest Allocation for the related Distribution Date; provided, however, that for purposes of determining the Required Daily Deposit Target Finance Charge Amount on any day on which the Class A(2008-C) Tranche Interest Allocation cannot be determined because the Note Interest Rate for the applicable Interest Accrual Period has not yet been notified to the Calculation Agent and the Indenture Trustee in accordance with the Note Purchase Agreement, the Required Daily Deposit Target Finance Charge Amount shall be the Class A(2008-C) Tranche Interest Allocation determined based on a pro forma calculation made on the assumption that the Note Interest Rate will be equal to the sum of (i) the Note Interest Rate, excluding any applicable margin, for the prior

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Interest Accrual Period and applicable to the Interest Payment Date occurring in such Due Period, multiplied by 1.25 and (ii) any applicable margin; provided , further , that for purposes of determining the Required Daily Deposit Target Finance Charge Amount for any day in the Due Period preceding the first Interest Payment Date on which the Outstanding Dollar Principal Amount of the Class A(2008-C) Notes is greater than zero, if the Class A(2008-C) Tranche Interest Allocation cannot be determined because the Note Interest Rate for such first Interest Accrual Period has not yet been notified to the Calculation Agent and the Indenture Trustee in accordance with the Note Purchase Agreement, a rate equal to the rate provided by the Agent, based on the Agent’s good faith estimate of the anticipated Note Interest Rate for such first Interest Accrual Period, to the Indenture Trustee and Calculation Agent on the date of effectiveness of such first increase in the Outstanding Dollar Principal Amount of the Class A(2008-C) Notes shall be used in lieu of the Note Interest Rate.

“ Required Daily Deposit Target Principal Amount ” means, for any day in a Due Period, (i) if such Du