When assembling a camping tent, we sometimes have to put the tent poles through a kind of tunnel created using a strip of the same fabric of which the tent is made.
The Russian term for this channel (tunnel? pocket?) is kuliska (кулиска). I wonder what the English term is for this.
On the image, you can see a tent pole that creates the camping tent's frame (каркас). This tent pole emerges from a "kuliska" and then dives into another "kuliska".
Multitran offers several translations but I'm not sure they fit.
The same word is used in Russian for the channel in which we put a decorative band or a belt or string to support a piece of clothing: