I am trying to replace my tub spout because the shower diverter isn't working well. So, I unscrewed the old spout and found that the pipe from the wall has a coupling attached to it. On the inside of the old spout there's a tiny threaded pipe attached to it so that it can reach the coupling and screw it in. My question is, on my new tub spout it doesn't have that tiny threaded pipe that extends the reach to the coupling...is there a name for that piece or is it just a piece of cut pipe? Thanks for your help!

hard to tell from your terminology...
do you see a picture of it here? does that help?
[www.google.com]

Close nipple ? All thread nipple ?

<a href="[s3.photobucket.com]; target="_blank"><img src="[i3.photobucket.com]; border="0" alt=" photo 14505325727021729922508.jpg"/></a> here's a picture of the attaching part

<a href="[s3.photobucket.com]; target="_blank"><img src="[i3.photobucket.com]; border="0" alt=" photo 14505325727021729922508.jpg"/></a> the old one is the one on the right...has additional pipe extension inside...that's what I need a name for

You need a short brass "nipple" the correct length to reach from the coupling to the thread in your spout. You have to measure to determine the proper length. Do not forget to add a little bit to allow for it to tighten up.