Linux finally grows up
It's quite possible that Linus Torvalds didn't realise what he was starting when he first honed the concept of open source software into a suggested operating environment called Linux.
If that wording seems obtuse, it's because of the particular rigours of discussion about Linux and open-source software in public. For example, "What is Linux?" would seem a simple question with a simple answer: it's an operating system.
But say or write that in public and the open source dogs of war will descend on you. Linux is a specification, an outline, a concept, a set of rules, a set of components, or a set of something else, depending on who you ask.
Solaris is an operating system, Linux isn't. Red Hat Linux is - sort of. Should you care? Absolutely not.