Brazing is a way of sticking two pieces of metal together. When you glue things together, you use a substance that sticks to both things and hardens. But when you want to stick metal pieces together, you can't use glue because it won't stick very well.
That's where brazing comes in. With brazing, you melt a special metal that has a lower melting point than the metal you want to stick together. This special metal is called a filler material. You heat up the metal pieces you want to stick together until they get really hot. Then you add the filler material to the gap between the pieces. The filler material melts and flows into the gap, sticking the two pieces of metal together.
Think of it like putting a puzzle together. Except instead of using glue to keep the pieces in place, you're using a special metal that melts and fuses the pieces together permanently.
Brazing is used in all kinds of things, from making bicycles to building cars or airplanes. It's a very strong way of joining metal and can handle a lot of stress and pressure. So, if you ever need to stick two pieces of metal together, remember the word "brazing"!