An indication of willingness to do or refrain from doing something that is capable of being converted by acceptance into a legally binding contract. It is made by an offeror to an offeree and is capable of acceptance only by an offeree who knows of its existence (Taylor v Allon  1 QB 304). Thus, a person giving information cannot claim a reward if he did not know that a reward was being offered. An offer must be distinguished from an invitation to treat, which is an invitation to others to make offers, as by displaying goods in a shop window (Gibson v Manchester City Council  1 WLR 294 (CA); Fisher v Bell  1 QB 394). It must also be distinguished from a declaration of intention, which is a mere statement of intent to invite offers in the future, as by advertising an auction. See also counteroffer; lapse of offer; rejection of offer; revocation of offer.