1) a castle, stronghold, fortress, fastness
2) anything on which one relies
2a) of the arguments and reasonings by which a disputant endeavours to fortify his opinion and defend it against his opponent
Part of Speech: noun neuter
Citing in TDNT: 5:590, 752
From a remote derivative of G2192 (meaning to fortify, through the idea of holding safely); a castle (figuratively argument): - stronghold.
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 ὀχύρωμα; click on the second column to search for that grammatical form of the root ὀχύρωμα; click on the third column to search for that word and grammatical form; click on the total to search for the root ὀχύρωμα.