SAP

Hi all:

New to the forum so a big hello to you all!

This is a silly question, however I would like to know exactly what SAP is? I know that SAP is a vast area covering a variety of topics,one only has to look at the variety of topics covered in this forum, however I have limited knowledge of SAP. Could it be described as an O/S for business users?

Any information someone can supply would be greatly appreciated.

Thanks