'Coupon' definitions:

Definition of 'coupon'

noun

A negotiable certificate that can be detached and redeemed as needed [syn: coupon, voucher]

noun

A test sample of some substance

From: GCIDE

Coupon \Cou"pon\ (k??"p?n; F. k??`p?n"), n. [F., fr. couper to cut, cut off. See Coppice.]
1. (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. [1913 Webster]
2. 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. [1913 Webster]
3. a ticket or form allowing the bearer to purchase a specific quantity of rationed goods; -- such coupons are typically issued by a governmental agency. [PJC]
4. 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. [PJC]