heart 
(härt)
(härt)n.
1. Anatomy
a. The chambered muscular organ in vertebrates that pumps blood received from the veins into the arteries, thereby maintaining the flow of blood through the entire circulatory system.
b. A similarly functioning structure in invertebrates.
2. The area that is the approximate location of the heart in the body; the breast.
3.
a. The vital center and source of one's being, emotions, and sensibilities.
b. The repository of one's deepest and sincerest feelings and beliefs: an appeal from the heart; a subject dear to her heart.
c. The seat of the intellect or imagination: the worst atrocities the human heart could devise.
4.
a. Emotional constitution, basic disposition, or character: a man after my own heart.
b. One's prevailing mood or current inclination: We were light of heart.
5.
a. Capacity for sympathy or generosity; compassion: a leader who seems to have no heart.
b. Love; affection: The child won my heart.
6.
a. Courage; resolution; fortitude: The soldiers lost heart and retreated.
b. The firmness of will or the callousness required to carry out an unpleasant task or responsibility: hadn't the heart to send them away without food.
7. A person esteemed or admired as lovable, loyal, or courageous: a dear heart.
8.
a. The central or innermost physical part of a place or region: the heart of the financial district.
b. The core of a plant, fruit, or vegetable, such as a heart of palm.
9. The most important or essential part: get to the heart of the matter.
10. A conventional two-lobed representation of the heart, usually colored red or pink.
11. Games
a. A red, heart-shaped figure on certain playing cards.
b. A playing card with this figure.
c. hearts (used with a sing. or pl. verb) The suit of cards represented by this figure.
d. A card game in which the object is either to avoid hearts when taking tricks or to take all the hearts.
tr.v. heart·ed, heart·ing, hearts
Idioms: 1. Slang To have great liking or affection for: I heart chocolate chip cookies!
2. Archaic To encourage; hearten.
at heart
In one's deepest feelings; fundamentally.
by heart
Learned by rote; memorized word for word.
do (one's) heart good
To lift one's spirits; make one happy.
from the bottom/depths of (one's) heart
With the deepest appreciation; most sincerely.
have (one's) heart in (one's) mouth
To be extremely frightened or anxious.
have (one's) heart in the right place
To be well-intentioned.
heart and soul
Completely; entirely.
in (one's) heart of hearts
In the seat of one's truest feelings.
lose (one's) heart to
To fall in love with.
near/close to (one's) heart
Loved by or important to one.
steal (someone's) heart
To win one's affection or love.
take to heart
To take seriously and be affected or troubled by: Don't take my criticism to heart.
to (one's) heart's content
To one's entire satisfaction, without limitation.
wear (one's) heart on (one's) sleeve
To show one's feelings clearly and openly by one's behavior.
with all (one's) heart
1. With great willingness or pleasure.
2. With the deepest feeling or devotion.
with half a heart
In a halfhearted manner.
[Middle English hert, from Old English heorte; see kerd- in the Appendix of Indo-European rootsV., sense 1, from the use of a heart shape to represent the verb love, originally between the letters I and NY in merchandise meant to be read I love New York.]