Number nine originally wearing gold ring (7)
I believe the answer is:
ordinal
'number' is the definition.
(ordinal number is a kind of number)
'nine originally wearing gold ring' is the wordplay.
'originally' says to take the initial letters.
'wearing' indicates putting letters inside.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'ring' becomes 'dial' (I've seen this before**).
The first letter of 'nine' is 'n'.
'or'+'dial'='ordial'
'n' put into 'ordial' is 'ORDINAL'.
(Other definitions for ordinal that I've seen before include "Ranking number" , "The associate of Cardinal" , "First, second, third could be such a numeral" , "E.g. first" , "Number which shows position in a series" .)