doyen
Concise Oxford English Dictionary © 2008 Oxford University Press:
doyen /ˈdɔɪən, ˈdwɑːjã/
▶noun (fem. doyenne /ˈdɔɪɛn, dɔɪˈɛn, dwʌˈjɛn/) the most respected or prominent person in a particular field.
'doyen' also found in these Oxford entries:

