Definition of "Sale" :
noun: a particular instance of selling
"He has just made his first sale."
noun: the general activity of selling
"They tried to boost sales."
noun: an occasion (usually brief) for buying at specially reduced prices
"They held a sale to reduce their inventory."
noun: an agreement (or contract) in which property is transferred from the seller (vendor) to the buyer (vendee) for a fixed price in money (paid or agreed to be paid by the buyer)
"The salesman faxed the sales agreement to his home office."
noun: the state of being purchasable; offered or exhibited for selling
"You'll find vitamin C for sale at most pharmacies."