Real Dictionary

discount
countable noun: A discount is a reduction in the usual price of something.
verb: If a shop or company discounts an amount or percentage from something that they are selling, they take the amount or percentage off the usual price.
verb: If you discount an idea, fact, or theory, you consider that it is not true, not important, or not relevant.

discount in American English
a reduction from a usual or list price
to lend or sell with discounts
to pay or receive the present value of (a bill of exchange, promissory note, etc.), minus a deduction to cover interest for the purchaser
intransitive verb: to advance or lend money after deduction of interest
noun: the act or an instance of discounting
transitive verb: to deduct a certain amount from (a bill, charge, etc.)

discount in British English
noun: a deduction from the full amount of a price or debt, as in return for prompt payment or to a special group of customers
verb: to leave out of account as being unreliable, prejudiced, or irrelevant

discount in Hospitality
noun: A discount is a reduction in the usual price of something.

discount in Retail 1
noun: When goods are offered at a discount their usual selling price is reduced.

discount in Retail 2
verb: If a store discounts goods, it reduces the usual price of the goods, often by a stated percentage or amount.