Heraldic symbol flourished over Europe, mostly tasteful (5-2-3)

I believe the answer is:

fleur-de-lis

I'm a little stuck... Click here to teach me more about this clue!

'heraldic symbol' is the definition.
'fleur-de-lis' can be an answer for 'symbol' (thesaurus). I'm not certain of the 'heraldic' bit.

'flourished over europe mostly tasteful' is the wordplay.
'flourished' becomes 'fl' (abbreviation in biographical entries).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'europe' becomes 'eur' (abbreviation for Europe).
'mostly tasteful' becomes 'delis' (I am not sure about this - if you are sure you should believe this answer much more).
'fl'+'eur'+'delis'='FLEUR-DE-LIS'

Can you help me to learn more?

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.