What is the word for the sewing thing - like a line along the seam?

I picked up some velvet at a yardsale.  It's only a yard square, so not really enough to do anything, but I wondered if it could be used for that thing I can't remember the name.

You cut a strip of cloth and then fold it around a cord.  Then somehow, this goes in the seam so it it shows up as a line on the outside of the fabric.  

If that's a real thing, what's it called so I can learn how to do it.

If it's not a real thing, then I probably dreamed it.  

Piping.

May Lotito wrote:Piping.

Ah ha!
Dang, it's not in my sewing book.  I'll just have to watch YouTube.

Thanks.
Ps, glad it is a real thing.

As far as I know, cording is synonym to piping.

Ah ha.  The book calls it cording.   Thanks.