(i.e. kidneys). In the ancient system of physiology the kidneys were believed to be the seat of desire and longing, which accounts for their often being coupled with the heart. (Psalms 7:9; 26:2; Jeremiah 11:20; 17:10), etc.
·noun ·pl The kidneys; also, the region of the kidneys; the loins. II. Reins ·noun ·pl The inward i...
Webster's Dictionary of the English Language
The kidneys, the supposed seat of the desires and affections; used metaphorically for "heart." The "...
Easton's Bible Dictionary