One mathematical figure regarded as symbolic (6)
I believe the answer is:
iconic
'symbolic' is the definition.
(I've seen this before)
'one mathematical figure' is the wordplay.
'one' becomes 'i' (Roman numeral).
'mathematical figure' becomes 'conic' (conic is a kind of figure. I am not sure about the 'mathematical' bit.).
'i'+'conic'='ICONIC'
'regarded as' acts as a link.
Can you help me to learn more?
(Other definitions for iconic that I've seen before include "much revered" , "Having the characteristics of revered person" , "Like a symbol/image" , "Symbolic, emblematic" , "Very famous" .)