Linux (often pronounced LIH-nuhks with a short "i") is a Unix-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive Unix systems.
The big difference here comes down to what we mean by Linux. People use the term “Linux” to mean many different things. At its most basic, Linux means the Linux kernel. A kernel is the core part of any operating system.