2a) either from three to six o'clock p.m.
2b) from six o'clock p.m. to the beginning of night
Part of Speech: adjective
From G3796; late; feminine (as noun) afternoon (early eve) or nightfall (later eve): - even (-ing, [-tide]).
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root ὀψία; click on the second column to search for that grammatical form of the root ὀψία; click on the third column to search for that word and grammatical form; click on the total to search for the root ὀψία.