Fusing is the joining of glass while in it's molten state. It is what happens to each gather of glass added to the piece being worked, a fundamental step in all glassblowing. It also is used to describe work done in a kiln or an oven where the pieces of glass are allowed to fuse together while hot.
This is a technique of using heat to bond two items together. I might have invented the technique of fusing large pieces of fine silver to glass. As far as I know, it was new to the Society of Glass Beadmakers conventions I have attended. If I find earlier history of this technique, I will update this definition.
The melting or bonding of units together by heat.