I see. We call the entire outside the crust. So the heel also has a crust.
Bread crusts are the best part of fresh bread and the worst part of sliced, supermarket bread. I wonder how that works.
According to this, the heel is also the butt end.
Another UK voice here. Yes, it’s ‘crust’ for the slices at either end, and also for the tougher part forming the perimeter of any individual slice. (We just invented the language. We didn’t say it made any sense.)
Supplement: a Scottish cow-orker from my past told me that in her country the end bits were called ‘bumpers’, a word not featured in this thread thus far.
Supplement #2: I am one of those who crave the crust (‘bits at either end’) more than any other part of the loaf, especially for toast. I once worked at an office where toast-making was a ritualised start to each working day. I was in heaven because everyone else hated / avoided the crusts, meaning all the more for me. I should have stayed there forever, really, because life doesn’t get any better than that.
Supplement #3: Many times in my life, people have suggested that it doesn’t make any sense to toast a crust, because one side is already ‘toasted’. The answer is either (a) no, you’re wrong, one side of the crust may be distinct from the rest of the loaf but it does not have the presence, texture or taste of an actual toasted side and so it is worth toasting, or (b) yes, you’re right, it doesn’t really make sense but I still do it and enjoy it.
I am not sure which, and it doesn’t seem a very inspired use of my time either debating it or worrying about it, but I have done from time to time.
Supplement #4: I think the UN should be pioneering some sort of exchange program, so that people like me (who wish that every slice could be a crust, especially for toast) can be do a deal with the majority (who want to avoid the crust for their toast). Then we’d all be better off and, I suspect, world peace would ensue.
Supplement #5: Those of my friends who maintain that I could write 10,000 words (all rubbish) about anything will look upon this post and sigh despairingly, at the same time relishing another prize exhibit for their case.
I’ve always known it as “the kissing crust”. I used to beg for it from a fresh crusty loaf, with butter and honey, or more like it, vegemite.
Hey! Join our campaign to foist the name “kiss” on the unsuspecting world! 
Oh dear.
An ex-boyfriend’s family called it the ‘gunderba’ or ‘gundeba’. They were American of German descent. I have never heard this or any sound-alikes elsewhere. The Google, it does nothing!
Confirmed by my source as well.
My Dad always told me it was called an " Ecliet " ( E KLY ETT ) he grew up during the depression, grew up in SLC but never heard anything but the Heel so thats my 2cents
Another UKer calling crust.
Yes, the crust is the harder bit on the outside of the loaf. But the ‘crust’ is also the ends which are at least 50% covered in crust.
Me too, although I was aware of ‘heel’. Never ever heard it called a butt. Of course but or butt has other meanings than arse. Rifles have a butt for example.
Welcome to the message board, Ted. This is an older thread (what we call a “zombie thread”) so some of the older posters in this thread may not be around to answer.
You can call it anything you want, but it won’t answer you.
I call mine Roger.
My father called it the “ka-nip” accent on second syllable; never saw it written. He dealt with people of several ethnicities, don’t know which it might have been; altho I might guess Yiddish.
Could the OP just be confusing putka for shpitzel?
I’m sure that, with some effort, one could write 10,000 words in less than 8 years. If you’re still here, ianzin, you have 9643 words still to go.
It is the crust in the UK.
I never heard it was called the heel or butt, so I suppose those words are common in US English.
Another one to at to the UK - USA English dictionary of everyday terms.
“Shpitzel” is a funny sounding word. Yiddish has a lot of them, I guess, but its English translation “snood” out-shpitzels shpitzel.
Snood it is then.
SWMBO calls it the “assy bit” as she has no truck with chewy crusts. I however, cherish them and call them delicious butter and cheese holders.
Not that the OP wil ever see this, but I would have called it ‘dupka’ (pronounced doop-kuh). Diminutive of dupa - Polish for ass.