Frank - there is a list of useful vocabulary “behind” the blue link, below the other vocabulary to check. Not all exercises have these, and I have overlooked them previously too.

You are right about ‘police’ meaning ‘font’ and ‘en gras’ means in bold typeset. 

A useful app is also the wordreference dictionary app. This particular definition for “police” is there in the Traductions supplémentaires section. 

Agree with Brian. Wordreference is not perfect but it is very good - especially so for common short phrases that can be hard to track down elsewhere, and for which deepL/google are less reliable I find.