or chiefly Britishaeon/ˈiːˌɑːn/
or chiefly British aeon /ˈiːˌɑːn/
Learner's definition of EON
: a very long period of time — usually plural
Over the eons, the river changed its course many times.
(informal) How have you been? I haven't seen you in eons! [=ages]