1) a setting or placing under
1a) thing put under, substructure, foundation
2) that which has foundation, is firm
2a) that which has actual existence
2a1) a substance, real being
2b) the substantial quality, nature, of a person or thing
2c) the steadfastness of mind, firmness, courage, resolution
2c1) confidence, firm trust, assurance
Part of Speech: noun feminine
Citing in TDNT: 8:572, 1237
From a compound of G5259 and G2476; a setting under (support), that is, (figuratively) concretely essence, or abstractly assurance (objectively or subjectively): - confidence, confident, person, substance.
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 ὑπόστασις; click on the second column to search for that grammatical form of the root ὑπόστασις; click on the third column to search for that word and grammatical form; click on the total to search for the root ὑπόστασις.