I've been searching this site all over but does anyone know what tcr means I have to get a back-up retainer with "TCR".does anyone know what that means and where it is placed?I forgot to ask my ortho...

I've never heard the term, but some orthos use different lingo in their offices than what is most common.

I can think of three kinds of retainers:

Hawley - traditional retainer with acrylic plate on the roof of the mouth and a wire across the teeth hawley retainer - Google Image Search

Essix - looks like an Invisalign tray essix retainer - Google Image Search

Bonded/fixed - wire that is attached to the back of your teeth (usually the front 4 or 6) to hold them in place. Some orthos use this in addition to one of the other two retainers. bonded retainer - Google Image Search

If you have a question, call your orthos office in the morning and ask. Remember, YOU (or your parents) paid THEM; they are there to help and answer your questions! :)

Best suggestion... call your orthodontist in the morning. The receptionist should be able to tell you what a TCR is. I myself have never heard that term.