FROM STRONG’S GREEK DICTIONARY (1890)

Strong’s Greek Dictionary (1890) — public domain, printed whole.

opisthen ὄπισθεν — op'-is-then — from opis (regard; from 3700) with enclitic of source; from the rear (as a secure aspect), i.e. at the back (adverb and preposition of place or time):--after, backside, behind.

see GREEK for 3700