advance against royalties，可以理解为“特许权使用费的保底费”，就是当知识产权许可协议签署后，被许可方向权利人支付的首笔特许权使用费。

特许权使用费一般来说都是按销售收入的一定比例支付，比如5%， 但是销售情况不一定很好，如果没有销售，许可方就拿不到特许权使用费。为了向许可方提供更大的利益保证，要先向其支付一笔advance against royaltities, 不论有无销售，许可方已经拿到了一笔费用保底。这笔费用可以从根据实际销售收入计算的5%提成中扣除。

至于如何定义，现在并无见到特别好的中文定义，建议翻译为：特许权使用费首付款。首付款就是预付的特许权使用费，并且可以根据实际销售情况抵扣，只是若无实际销售不退回而已。

请参考Wiki的解释：

In the field of intellectual property licensing, an advance against royalties is a payment made by the licensee to the licensor at the start of the period of licensing (usually immediately upon contract, or on delivery of the property being licensed) which is to be offset against future royalty payments. It is also known as a guaranteed minimum royalty payment.

For example, a book's author may sell a license to a publisher in return for 5% royalties on sales of the book and a $5,000 advance against those royalties. In this case, the author would immediately receive the $5,000, and royalty payments would be withheld until $5000 in royalties already paid had been earned — that is, until the publisher's takings from selling copies of the book reached $100,000; after that point the 5% royalty would be paid on any additional sales.[1] [2]

In some business areas (e.g. film production), it is common practice for the licensee to demand repayment of any advance that is not covered by royalties, whereas in others (e.g. book publication) this practice is unusual.

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