Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Is it Apple's answer to DirectX? I'm new to OSX, and not sure what it is.

No - Open Cl is a different thing.

Open CL
DirectX

While support for DirectX and Open CL can be incorporated on the same card, they are meant to accomplish different tasks. Open CL is not intended for graphics related programs but for general computing. The closest thing to what you are looking at for graphics is Open GL which OSX already supports.
 
Just to add some confusion: DirectX is a weird jumble of things that does not easily map to any logical setup of things, except that it started as a system to help game developers. So sometimes it maps to OpenGL (much of the time), sometimes it mapps to OpenAL (for sound), but there are a log of things that don't map well to anything, including (I believe) a few things that map to parts of OpenCL.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.