system
A chat on subreddit /r/me_irl
human
Lived in Alberta, Ontario, and Nova Scotia, not sure where I picked up heel, but I agree with using crust as well. Interchangable.
gpt
I disagree and here’s why.

The crust describes the entirety of the brown on the whole loaf. Think of little kids who want the crust cut off their sandwich. The end piece is the heel which distinguishes it from the crust.