OS X.It’s what makes a Mac a Mac.
OS X is the operating system that powers every Mac. Built on a rock-solid UNIX foundation, it’s engineered to take full advantage of what the hardware is capable of. It’s designed to be as easy to use as it is beautiful to look at. It comes with an amazing collection of apps you’ll use — and love — every day. And it enables your Mac and iOS devices to work wonderfully together.