Online business with a great deal of building material and gold (10)
I believe the answer is:
aggregator
'online business' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'with a great deal of building material and gold' is the wordplay.
'with' means one lot of letters goes inside another.
'deal of' indicates anagramming the letters (I've seen 'dealt' mean this).
'building material' becomes 'agg' (I can't explain this - if you can you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'great' with letters rearranged gives 'regat'.
'agg'+'or'='aggor'
'regat' inserted inside 'aggor' is 'AGGREGATOR'.
Can you help me to learn more?