ἀνάγαιον [2 verses]( noun sg neut acc ) "Upper room" is  anōgeon, which means "upper room" from its literal meaning "high ground". -- "Upper room" is  from a Greek word that only appears in this verse and the parallel verse in Mark. It gets the meaning  "upper room" from its literal meaning "high ground". This word is not used anywhere else in ancient Greek in the Perseus database. Nor does it appear in the Septuagint, which is very unusual. This may have been a local Greek word not in common use elsewhere.