It seems to me that the term "eparchy" is very infrequently used these days in the formal titling of the canonical jurisdictions in most of the Orthodox Churches, both Eastern and Oriental. Although one will see it used in documents, articles, etc., the formal name of the jurisdiction as publicly displayed on letterhead, publications, webpages, etc., invariably is styled as "diocese".
Although this is most true in the US, it certainly applies elsewhere in the world as well. In looking at some patriarchal websites recently, I was struck by the fact that the usage seemed to be global.
Does anyone have any thoughts on why this is so. Is it a case of the Churches catering to commonly understood phraseology? (Interestingly, many Eastern Catholic Churches tend to use "eparchy" to the exclusion of "diocese", although for a few usage seems to be mixed.)