in reference to seas covering continental shelves, 1915, from Greek ēpeiros "mainland, land, continent" (as opposed to the sea and the islands), from PIE root *apero- "shore" (source also of Old English ofer "bank, rim, shore," Old Frisian over "bank") + -ic.
As the term "continental deposits" in this sense is now ingrained in Geology, we can no longer use Dana's "continental seas" without raising a question in the mind as to what is meant when their deposits are considered. For this reason we propose here to use epeiric seas (meaning seas that lie upon the continents) for the bodies of water that lie within the continents in the downwarps of the continental masses. [Louis V. Pirsson, "A Text-Book of Geology," 1915]