The anatomy of a knife can be a bit crazy because there are so many different knife styles and not all knives have all the parts. Further, we're not likely taught the parts in grade school. And, if we were, that was a long time ago. So, what's a knife heel anyway?
Great question. The heel of a knife is a part of the cutting edge. All knives have a heel. It's the back part, or the part closest to the handle of the knife. It's opposite the tip of the knife (where the cutting edge and the spine, or top, of the blade come together.)
The heel is often used for big cutting tasks with fibrous vegetables and/or meat. This is often a cut where you might desire more force than a normal cut.
So, there we have it. The heel of a knife is the portion of the cutting edge closest to the handel. Viola.