1) the highest part of the house, the upper rooms or story where the women resided
2) a room in the upper part of a house, sometimes built upon the flat roof of the house, whither Orientals were wont to retire in order to sup, meditate, pray
Part of Speech: noun neuter
Neuter of a derivative of G5228; a higher part of the house, that is, apartment in the third story: - upper chamber (room).
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
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 ὑπερῷον; click on the second column to search for that grammatical form of the root ὑπερῷον; click on the third column to search for that word and grammatical form; click on the total to search for the root ὑπερῷον.