Should common terms by emphasized/typeset in a consistent way?

[kbeyls]

Some parts of the book emphasize common terms.
Those are terms that typically would go into the index.
We probably ought to have a consistent way to typeset those across the book.

Should we have a macro to make that easy? e.g. a macro that both typesets the introduced/common term in a consistent way + adds it to the index?

If we decide to stick with a typesetting convention for this, we should also write up that convention in the writing style guidelines.