noun: fulcrum; plural noun: fulcra; plural noun: fulcrums:

the point on which a lever rests or is supported and on which it pivots.

When I was first learning how to do stained glass, I was scoring a sheet of glass and surprisingly it broke into a few pieces. This is because there was a tiny chip of glass left on the table, underneath the sheet I was cutting. This tiny glass chip had created a fulcrum, causing my glass sheet to break over it as pressure was applied while scoring. I had not swept the area clean before cutting. This became a running joke around the store and I got very used to hearing the word fulcrum. I still remembered that 20 years later and couldn't resist incorporating it into my own business name and logo. And it sounded cool too.