Source : Webster's Revised Unabridged Dictionary (1913)

Heart \Heart\, n. [OE. harte, herte, heorte, AS. heorte; akin to
   OS. herta, OFies. hirte, D. hart, OHG. herza, G. herz, Icel.
   hjarta, Sw. hjerta, Goth. ha['i]rt?, Lith. szirdis, Russ.
   serdtse, Ir. cridhe, L. cor, Gr. ?, ? ????. Cf. {Accord},
   {Discord}, {Cordial}, 4th {Core}, {Courage}.]
   1. (Anat.) A hollow, muscular organ, which, by contracting
      rhythmically, keeps up the circulation of the blood.

            Why does my blood thus muster to my heart! --Shak.

   Note: In adult mammals and birds, the heart is
         four-chambered, the right auricle and ventricle being
         completely separated from the left auricle and
         ventricle; and the blood flows from the systematic
         veins to the right auricle, thence to the right
         ventricle, from which it is forced to the lungs, then
         returned to the left auricle, thence passes to the left
         ventricle, from which it is driven into the systematic
         arteries. See Illust. under {Aorta}. In fishes there
         are but one auricle and one ventricle, the blood being
         pumped from the ventricle through the gills to the
         system, and thence returned to the auricle. In most
         amphibians and reptiles, the separation of the auricles
         is partial or complete, and in reptiles the ventricles
         also are separated more or less completely. The
         so-called lymph hearts, found in many amphibians,
         reptiles, and birds, are contractile sacs, which pump
         the lymph into the veins.

   2. The seat of the affections or sensibilities, collectively
      or separately, as love, hate, joy, grief, courage, and the
      like; rarely, the seat of the understanding or will; --
      usually in a good sense, when no epithet is expressed; the
      better or lovelier part of our nature; the spring of all
      our actions and purposes; the seat of moral life and
      character; the moral affections and character itself; the
      individual disposition and character; as, a good, tender,
      loving, bad, hard, or selfish heart.

            Hearts are dust, hearts' loves remain. --Emerson.

   3. The nearest the middle or center; the part most hidden and
      within; the inmost or most essential part of any body or
      system; the source of life and motion in any organization;
      the chief or vital portion; the center of activity, or of
      energetic or efficient action; as, the heart of a country,
      of a tree, etc.

            Exploits done in the heart of France. --Shak.

            Peace subsisting at the heart Of endless agitation.
                                                  --Wordsworth.

   4. Courage; courageous purpose; spirit.

            Eve, recovering heart, replied.       --Milton.

            The expelled nations take heart, and when they fly
            from one country invade another.      --Sir W.
                                                  Temple.

   5. Vigorous and efficient activity; power of fertile
      production; condition of the soil, whether good or bad.

            That the spent earth may gather heart again.
                                                  --Dryden.

   6. That which resembles a heart in shape; especially, a
      roundish or oval figure or object having an obtuse point
      at one end, and at the other a corresponding indentation,
      -- used as a symbol or representative of the heart.

   7. One of a series of playing cards, distinguished by the
      figure or figures of a heart; as, hearts are trumps.

   8. Vital part; secret meaning; real intention.

            And then show you the heart of my message. --Shak.

   9. A term of affectionate or kindly and familiar address. ``I
      speak to thee, my heart.'' --Shak.

   Note: Heart is used in many compounds, the most of which need
         no special explanation; as, heart-appalling,
         heart-breaking, heart-cheering, heart-chilled,
         heart-expanding, heart-free, heart-hardened,
         heart-heavy, heart-purifying, heart-searching,
         heart-sickening, heart-sinking, heart-stirring,
         heart-touching, heart-wearing, heart-whole,
         heart-wounding, heart-wringing, etc.

   {After one's own heart}, conforming with one's inmost
      approval and desire; as, a friend after my own heart.

            The Lord hath sought him a man after his own heart.
                                                  --1 Sam. xiii.
                                                  14.

   {At heart}, in the inmost character or disposition; at
      bottom; really; as, he is at heart a good man.

   {By heart}, in the closest or most thorough manner; as, to
      know or learn by heart. ``Composing songs, for fools to
      get by heart'' (that is, to commit to memory, or to learn
      thoroughly). --Pope.

   {For my heart}, for my life; if my life were at stake. [Obs.]
      ``I could not get him for my heart to do it.'' --Shak.

   {Heart bond} (Masonry), a bond in which no header stone
      stretches across the wall, but two headers meet in the
      middle, and their joint is covered by another stone laid
      header fashion. --Knight.

   {Heart and hand}, with enthusiastic co["o]peration.

   {Heart hardness}, hardness of heart; callousness of feeling;
      moral insensibility. --Shak.

   {Heart heaviness}, depression of spirits. --Shak.

   {Heart point} (Her.), the fess point. See {Escutcheon}.

   {Heart rising}, a rising of the heart, as in opposition.

   {Heart shell} (Zo["o]l.), any marine, bivalve shell of the
      genus {Cardium} and allied genera, having a heart-shaped
      shell; esp., the European {Isocardia cor}; -- called also
      {heart cockle}.

   {Heart sickness}, extreme depression of spirits.

   {Heart and soul}, with the utmost earnestness.

   {Heart urchin} (Zo["o]l.), any heartshaped, spatangoid sea
      urchin. See {Spatangoid}.

   {Heart wheel}, a form of cam, shaped like a heart. See {Cam}.
      

   {In good heart}, in good courage; in good hope.

   {Out of heart}, discouraged.

   {Poor heart}, an exclamation of pity.

   {To break the heart of}.
      (a) To bring to despair or hopeless grief; to cause to be
          utterly cast down by sorrow.
      (b) To bring almost to completion; to finish very nearly;
          -- said of anything undertaken; as, he has broken the
          heart of the task.

   {To find in the heart}, to be willing or disposed. ``I could
      find in my heart to ask your pardon.'' --Sir P. Sidney.

   {To have at heart}, to desire (anything) earnestly.

   {To have in the heart}, to purpose; to design or intend to
      do.

   {To have the heart in the mouth}, to be much frightened.

   {To lose heart}, to become discouraged.

   {To lose one's heart}, to fall in love.

   {To set the heart at rest}, to put one's self at ease.

   {To set the heart upon}, to fix the desires on; to long for
      earnestly; to be very fond of.

   {To take heart of grace}, to take courage.

   {To take to heart}, to grieve over.

   {To wear one's heart upon one's sleeve}, to expose one's
      feelings or intentions; to be frank or impulsive.

   {With all one's whole heart}, very earnestly; fully;
      completely; devotedly.