this is a more general term than discount so it covers all sorts of deductions to the invoice

Discount = the amount of deductions/reduction in price to be applied to the total of the invoice


http://dictionary.reference.com/browse/discount

discount
- 7 dictionary results
dis·count
   [v. dis-kount, dis-kount; n., adj. dis-kount] Show IPA
–verb (used with object)
1.
to deduct a certain amount from (a bill, charge, etc.): All bills that are paid promptly will be discounted at two percent.
2.
to offer for sale or sell at a reduced price: The store discounted all clothing for the sale.

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Note added at 1 hr (2011-08-19 08:12:43 GMT)
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avgå – ... (räkning) to be deducted / ... avgående poster - deductible items, items to be deducted ...

< Svensk-Englesk Fackordbock, för näringsliv, förvaltning, undervisning och forskning / A Swedish-English Dictionary of Technical Terms used in Business, Industry, Administration, Education and Research
av Ingvar E. Gullberg, Auktoriserad Translator
P.A. Norstedt & Söners Förlag, Stockholm

First Edition
© Ingvar E. Gullberg 1964
Kungl. Boktryckeriet P.A. Norstedt & Söner
Stockholm1964


http://www.thefreedictionary.com/discount

discount
noun
deduction, cut, reduction, concession, allowance, rebate, cut price, lower price, marked-down price You often get a discount on discontinued goods.

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Note: Discount or markdown at the time of sale.

Also could be a rebate after the time of sale - but this usually requires the consumer/customer/buyer to submit documentation and other data to the issuer of the rebate (the manufacturer of the product or other party) via mail, etc., in order to receive the rebate.