> When investing in someone's business, what is royalty?

When investing in someone's business, what is royalty?

Posted at: 2014-12-05 
It is basically a percentage of every sale of the product FOREVER.

I'm watching Shark Tank and I don't understand a certain thing. So if an offer is made, for example 50% of the company for $x, I understood that the investor would make 50% of the company's profit. But I saw one guy who wanted to pay $50k for 50% of the company and he offered 7% of royalty. What is the royalty? I don't know much about business, so I would appreciate some help. Thank you.