newbie and xterm cut and paste

[joe mc cool]

xfce 3.8.18 on a Debian 2.2.20 Linux machine (Both super systems, thanks a lot.)

I know this is probably a FAQ, but my searches of the archive have been unproductive:

how do I cut and paste from one application to another, or from one xterm to another ?

I can remember on a solaris box I was able to highlight the text on one window and simply click both buttons to paste it on another window.  My two xterms may or may not be open on the same machine.  I need to be able to cut and paste say from command lines or to/from xemacs to/from mozilla.

Perhaps I am asking the impossible.

TIA.

Joe.