Stories We Like: A Guide to the Comma
c.1400, "office or position of a sovereign," also "magnificence," from or modeled on Old French roialte (12c., Modern French royauté), from Vulgar Latin *regalitatem (nominative *regalitas), from Latin regalis (see royal). Sense of "prerogatives or rights granted by a sovereign to an individual or corporation" is from late 15c. From that evolved more general senses, such as "payment to a landowner for use of a mine" (1839), and ultimately "payment to an author, composer, etc." for sale or use of his or her work (1857). Cf. realty.
A payment made for some right or privilege, as when a publisher pays a royalty to an author for the author's granting the publisher the right to sell the author's book.
in law, the payment made to the owners of certain types of rights by those who are permitted by the owners to exercise the rights. The rights concerned are literary, musical, and artistic copyright; patent rights in inventions and designs; and rights in mineral deposits, including oil and natural gas. The term originated from the fact that in Great Britain for centuries gold and silver mines were the property of the crown; such "royal" metals could be mined only if a payment ("royalty") were made to the crown