You might not think you'd come across this word very often, but believe it or not (and though I can't place any specific instances), this is one I've heard quite a few times. I swear it isn't part of my normal repertoire, though!
What the Japanese know as a "T-back" (Tバック) , we know as...
Yes, the noble thong. I guess the name is apt enough - not really much need to ponder the meaning of the Japanese for this one.
japanese english|Let's Enjoy Japanese|t-back|thong|Tバック|underwear|和製英語|日本語|