unilateral contract
Binding agreement created by an offer that is accepted by a promise of performance
revocation
Offeror's act that invalidates an offer
offeree
Party to whom an offer is made
firm offer
Signed writing by a merchant promising to leave an offer open
counteroffer
Response by an offeree, with new terms, which ends the original offer
mirror image rule
Requirement that the terms in an acceptance exactly match the terms in the offer
acceptance
Affirmative response necessary to transform an offer into a contract
option
Contract to leave an offer open for a period of time in exchange for other consideration
contract
Agreement that is legally effective and enforceable in court
offer
Proposal that expresses willingness of the offeror to enter into a legally binding agreement