1) the midriff or diaphragm, the parts of the heart
2) the mind
2a) the faculty of perceiving and judging
Part of Speech: noun feminine
Citing in TDNT: 9:220, 1277
Probably from an obsolete φράω phraô (to rein in or curb; compare G5420); the midrif (as a partition of the body), that is, (figuratively and by implication of sympathy) the feelings (or sensitive nature; by extension [also in the plural] the mind or cognitive faculties): - understanding.
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 φρήν; click on the second column to search for that grammatical form of the root φρήν; click on the third column to search for that word and grammatical form; click on the total to search for the root φρήν.