As long as you document your research in the question, you'll probably be OK.
For your example questions
- Check Wikipedia:
"The body of a fibula is known as either the bow or the plate, depending on the basic form. A bow is generally long and narrow, and often arched. A plate is flat and wide."
- On a modern brooch, "bow" can also refer to a ribbon (or representation of a ribbon) shaped into a bow, for example. Don't assume that non-archaeologists will use the same terminology as archaeologists.
- In an archaeological context, a fitting is normally functional (like a handle, for example) while a furniture mount is more decorative (corner brackets might be an example). Unfortunately, people aren't always consistent in how they use the terms, and a handle in the shape of a dog is both decorative and functional.
