|When applied in relation to computers, Catalyst is a marketing name applied to a ATI graphics software. |
ATI are a major supplier of video hardware and Catalyst is the name of the software that is supplied with that hardware.
In short it is the name of the suit of applications that make your video hardware work, that is assuming you have an ATI Graphics card.
When applied literately it has a completely different but related meaning:
catalyst n. 1 substance that does not itself change, but speeds up a chemical reaction. 2 person or thing that precipitates change.