slough (plural sloughs) 1  The skin shed by a snake or other reptile. That is the slough of a rattler; we must be careful. 2  Dead skin on a sore or ulcer. This is the slough that came off of his skin after the burn.
The name Groupon is a combination of the words group and coupon, which references the company's viral marketing business model.
Definition of coupon for English Language Learners. : 1  a usually small piece of printed paper that lets you get a service or product for free or at a lower price. : 2  a section of an advertisement that you can cut out and mail to a company in order to request information or to order a product or service.