Words change and add meanings. Epicenter, meaning center (i. e. center of world finance) has been added to modern dictionaries .

Epi- Several applications; over (orig. meaning of epicenter), upon (epiphyte), besides (epiphenomenon), attached to (epididymis), outer (epiblast), after (epigenesis), etc. It had several of these meanings, depending on context, in the Greek.

Attempts to put a fence around a word (Uncle Dave O post) are doomed to failure.