If you look at the DFSORT manuals, everything you supply on the //SYSIN DD * is a "control card".
If you look at an IBM utility, it is highly likely that you tell it what to do with a "control card". Like IDCAMS, IEBCOPY, IEWL, etc, etc.
They are called "cards" because originally they were thin pieces of stiff cardboard with holes punched in them to represent characters. They are called "control" because you use them to tell a program, that can understand its own control cards, exactly what you want done. Or what you think you want done