coupon

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A code or detachable part of a ticket, card, or advertisement that entitles the holder to a certain benefit, such as a cash refund or a gift.
• noun A periodic interest payment due to the holder of a bond.
• noun The interest rate of a bond that pays a coupon.
• noun One of a set of small certificates that may be detached from a bond certificate and redeemed for interest payments.

from The Century Dictionary.

• noun A small piece of metal made as a part of another piece to serve as a sample for testing-purposes.
• noun A printed certificate or ticket attached to and forming part of an original or principal certificate or ticket, and intended to be detached when used.
• noun One of a series of conjoined tickets which bind the issuer to make certain payments, perform some service (as transportation over connecting railroad lines), or give value for certain amounts at different periods, in consideration of money received. At the settlement of each claim a coupon is detached and given up.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Com.) A certificate of interest due, printed at the bottom of transferable bonds (state, railroad, etc.), given for a term of years, designed to be cut off and presented for payment when the interest is due; an interest warrant.
• noun A section of a ticket, showing the holder to be entitled to some specified accomodation or service, as to a passage over a designated line of travel, a particular seat in a theater, or the like.
• noun a ticket or form allowing the bearer to purchase a specific quantity of rationed goods; -- such coupons are typically issued by a governmental agency.
• noun a printed form, often distributed as part of an advertisement, entitling the bearer to purchase a specific item of merchandise at a discount; or, a similar form which may be submitted to the issuer to obtain goods or information. Such coupons may be issued by the manufacturer (manufacturer's coupon) or by a retail establishment; in the latter case they may then be redeemed only at that particular retail store.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete A certificate of interest due, printed at the bottom of transferable bonds (state, railroad, etc.), given for a term of years, designed to be cut off and presented for payment when the interest is due; an interest warrant.
• noun finance Any interest payment made or due on a bond, debenture or similar (no longer by a physical coupon).
• noun A section of a ticket, showing the holder to be entitled to some specified accommodation or service, as to a passage over a designated line of travel, a particular seat in a theater, a discount, etc.
• noun Scotland The face.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a test sample of some substance
• noun a negotiable certificate that can be detached and redeemed as needed