1) name Hades or Pluto, the god of the lower regions
2) Orcus, the nether world, the realm of the dead
3) later use of this word: the grave, death, hell
Part of Speech: noun proper locative
Citing in TDNT: 1:146, 22
From G1 (as a negative particle) and G1492; properly unseen, that is, "Hades" or the place (state) of departed souls: - grave, hell.
|a world of the dead||1.19|
|(πύλαι ᾅδου) death (supernatural power)||12.50|
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 ᾅδης; click on the second column to search for that grammatical form of the root ᾅδης; click on the third column to search for that word and grammatical form; click on the total to search for the root ᾅδης.