Thayer's Greek Lexicon

 1. the heart
  1) that organ in the animal body which is the centre of the
circulation of the blood, and hence was regarded as the seat
of physical life
  2) denotes the centre of all physical and spiritual life
  1) the vigour and sense of physical life
  2) the centre and seat of spiritual life
2b1. the soul or mind, as it is the fountain and seat of the
thoughts, passions, desires, appetites, affections,
purposes, endeavours
2b2. of the understanding, the faculty and seat of the
intelligence
2b3. of the will and character
2b4. of the soul so far as it is affected and stirred in a
bad way or good, or of the soul as the seat of the
sensibilities, affections, emotions, desires,
appetites, passions
  3) of the middle or central or inmost part of anything, even
though inanimate