1) to make strong, strengthen
1a) of one's soul
Part of Speech: verb
From σθένος sthenos (bodily vigor; probably akin to the base of G2476); to strengthen, that is, (figuratively) confirm (in spiritual knowledge and power): - strengthen.
|make more able||74.14|
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 σθενόω; click on the second column to search for that grammatical form of the root σθενόω; click on the third column to search for that word and grammatical form; click on the total to search for the root σθενόω.