Classify gold and blood rose (5)
I believe the answer is:
order
'classify' is the definition.
(thesaurus)
'gold and blood rose' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'and' says to put letters next to each other.
'blood rose' becomes 'der' (I can't justify this - if you can you should give a lot more credence to this answer).
'or'+'der'='ORDER'
Can you help me to learn more?
(Other definitions for order that I've seen before include "Issue a command" , "peace" , "Group living under a religious rule" , "association" , "Directive for harmony" .)