The story
From porn (“pornography”) + hub (“a central facility providing a range of related services”), so-called because the website hosts pornographic videos; but Pornhub was originally part of a parent company called Interhub, which may have potentially inspired its name. Coined by founder Matt Keezer in May 2007. The noun sense is derived from the prominence of Pornhub.
Etymology from Wiktionary, CC BY-SA 4.0.