What’s the difference between 1st class ‘Honours’ as a grade result (like A* in A-levels) & ‘(Hons)’ as part of the BA/ BSc Degree title?

You tend to hear this word ‘Honours’ a lot in the context of British Universities, but I’ve noticed they’re prevalent in two distinct categories.

One is when describing the standard universal system of grading like heard in ‘1st Class Honours’ whilst its also used in the titles of degree courses itself especially as a differentiator like ‘BSc Economics (Hons)’ - so what does Honours even mean & does it have 2 separate meanings here or are they related?