1.  A hollow, muscular organ, which, by contracting rhythmically, keeps up the circulation of the blood. [1913 Webster]
" 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 systemic 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 systemic 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." [1913 Webster]
"Why does my blood thus muster to my heart!" [1913 Webster]

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. [1913 Webster]
"Hearts are dust, hearts' loves remain." [1913 Webster]

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. [1913 Webster]
"Exploits done in the heart of France." [1913 Webster]
"Peace subsisting at the heart
Of endless agitation." [1913 Webster]

4.  Courage; courageous purpose; spirit. [1913 Webster]
"Eve, recovering heart, replied." [1913 Webster]
"The expelled nations take heart, and when they fly from one country invade another." [1913 Webster]

5.  Vigorous and efficient activity; power of fertile production; condition of the soil, whether good or bad. [1913 Webster]
"That the spent earth may gather heart again." [1913 Webster]

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. [1913 Webster]

7.  One of the suits of playing cards, distinguished by the figure or figures of a heart; as, hearts are trumps. [1913 Webster]

8.  Vital part; secret meaning; real intention. [1913 Webster]
"And then show you the heart of my message." [1913 Webster]

9.  A term of affectionate or kindly and familiar address. Shak. [1913 Webster]
" 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-sore, heart-stirring, heart-touching, heart-wearing, heart-whole, heart-wounding, heart-wringing, etc." [1913 Webster]

   To give heart to; to hearten; to encourage; to inspirit. [1913 Webster]
"My cause is hearted; thine hath no less reason." [1913 Webster]

   To form a compact center or heart; as, a hearting cabbage. [1913 Webster]

heart, n.
1 a hollow muscular organ maintaining the circulation of blood by rhythmic contraction and dilation.
2 the region of the heart; the breast.
3 a the heart regarded as the centre of thought, feeling, and emotion (esp. love). b a person's capacity for feeling emotion (has no heart).
4 a courage or enthusiasm (take heart; lose heart). b one's mood or feeling (change of heart).
5 a the central or innermost part of something. b the vital part or essence (the heart of the matter).
6 the close compact head of a cabbage, lettuce, etc.
7 a a heart-shaped thing. b a conventional representation of a heart with two equal curves meeting at a point at the bottom and a cusp at the top.
8 a a playing-card of a suit denoted by a red figure of a heart. b (in pl.) this suit. c (in pl.) a card-game in which players avoid taking tricks containing a card of this suit.
9 condition of land as regards fertility (in good heart).

Idiom:
after one's own heart such as one likes or desires. at heart
1 in one's inmost feelings.
2 basically, essentially. break a person's heart overwhelm a person with sorrow. by heart in or from memory.
close to (or near) one's heart
1 dear to one.
2 affecting one deeply. from the heart (or the bottom of one's heart) sincerely, profoundly. give (or lose) one's heart (often foll. by to) fall in love (with). have a heart be merciful. have the heart (usu. with neg.; foll. by to + infin.) be insensitive or hard-hearted enough (didn't have the heart to ask him). have (or put) one's heart in be keenly involved in or committed to (an enterprise etc.). have one's heart in one's mouth be greatly alarmed or apprehensive. have one's heart in the right place be sincere or well-intentioned. heart attack a sudden occurrence of coronary thrombosis usu. resulting in the death of part of a heart muscle. heart failure a gradual failure of the heart to function properly, resulting in breathlessness, oedema, etc. heart-lung machine a machine that temporarily takes over the functions of the heart and lungs, esp. in surgery. heart of gold a generous nature. heart of oak a courageous nature. heart of stone a stern or cruel nature. heart-rending very distressing. heart-rendingly in a heart-rending way. heart's-blood lifeblood, life. heart-searching the thorough examination of one's own feelings and motives. heart to heart candidly, intimately. heart-to-heart adj. (of a conversation etc.) candid, intimate.
--n. a candid or personal conversation. heart-warming emotionally rewarding or uplifting. in heart in good spirits. in one's heart of hearts in one's inmost feelings. out of heart in low spirits. take to heart be much affected or distressed by. to one's heart's content see CONTENT(1). wear one's heart on one's sleeve make one's feelings apparent. with all one's heart sincerely; with all goodwill. with one's whole heart with enthusiasm; without doubts or reservations.

Derivative:
-hearted adj.

Etymology:
OE heorte f. Gmc

N  willingness, voluntariness, willing mind, heart, disposition, inclination, leaning, animus, frame of mind, humor, mood, vein, bent, penchant, aptitude, docility, docibleness, persuasibleness, persuasibility, pliability, geniality, cordiality, goodwill, alacrity, readiness, earnestness, forwardness, eagerness, asset, compliance, pleasure, gratuitous service, labor of love, volunteer, volunteering, willing, minded, fain, disposed, inclined, favorable, favorably- minded, favorably inclined, favorably disposed, nothing loth, in the vein, in the mood, in the humor, in the mind, ready, forward, earnest, eager, bent upon, predisposed, propense, docile, persuadable, persuasible, suasible, easily persuaded, facile, easy-going, tractable, genial, gracious, cordial, cheering, hearty, content, voluntary, gratuitous, spontaneous, unasked &c (ask), unforced, willingly, fain, freely, as lief, heart and soul, with pleasure, with all one's heart, with open arms, with good will, with right will, de bonne volonte, ex animo, con amore, heart in hand, nothing loth, without reluctance, of one's own accord, graciously, with a good grace, a la bonne heure, by all means, by all manner of means, to one's heart's content, yes.

N  intrinsicality, inbeing, inherence, inhesion, subjectiveness, ego, egohood, essence, noumenon, essentialness, essential part, quintessence, incarnation, quiddity, gist, pith, marrow, core, sap, lifeblood, backbone, heart, soul, important part, principle, nature, constitution, character, type, quality, crasis, diathesis, habit, temper, temperament, spirit, humor, grain, disposition, endowment, capacity, capability, moods, declensions, features, aspects, peculiarities, idiosyncrasy, oddity, idiocrasy, diagnostics, derived from within, subjective, intrinsic, intrinsical, fundamental, normal, implanted, inherent, essential, natural, innate, inborn, inbred, ingrained, inwrought, coeval with birth, genetous, haematobious, syngenic, radical, incarnate, thoroughbred, hereditary, inherited, immanent, congenital, congenite, connate, running in the blood, ingenerate, ingenite, indigenous, in the grain, bred in the bone, instinctive, inward, internal, to the manner born, virtual, characteristic, invariable, incurable, incorrigible, ineradicable, fixed, intrinsically, at bottom, in the main, in effect, practically, virtually, substantially, au fond, fairly, character is higher than intellect, come give us a taste of your quality, magnos homines virtute metimur non fortuna, non numero haec judicantur sed pondere, vital spark of heavenly flame.

N  importance, consequence, moment, prominence, consideration, mark, materialness, import, significance, concern, emphasis, interest, greatness, superiority, notability, weight, value, usefulness, gravity, seriousness, solemnity, no joke, no laughing matter, pressure, urgency, stress, matter of life and death, memorabilia, notabilia, great doings, red-letter day, great thing, great point, main chance, the be all and the end all, cardinal point, substance, gist, sum and substance, gravamen, head and front, important part, principal part, prominent part, essential part, half the battle, sine qua non, breath of one's nostrils, cream, salt, core, kernel, heart, nucleus, keynote, keystone, corner stone, trump card, salient points, top sawyer, first fiddle, prima donna, chief, triton among the minnows, 'it', important, of importance, momentous, material, to the point, not to be overlooked, not to be despised, not to be sneezed at, egregious, weighty, of note, notable, prominent, salient, signal, memorable, remarkable, unforgettable, worthy of remark, worthy of notice, never to be forgotten, stirring, eventful, grave, serious, earnest, noble, grand, solemn, impressive, commanding, imposing, urgent, pressing, critical, instant, paramount, essential, vital, all-absorbing, radical, cardinal, chief, main, prime, primary, principal, leading, capital, foremost, overruling, of vital importance in the front rank, first-rate, superior, considerable, marked, rare, significant, telling, trenchant, emphatic, pregnant, tanti, materially, in the main, above all, kat' exochin, par excellence, to crown all, to beat all, expende Hannibalem!.

N  affections, affect, character, qualities, disposition, nature, spirit, tone, temper, temperament, diathesis, idiosyncrasy, cast of mind, cast of soul, habit of mind, habit of soul, frame of mind, frame of soul, predilection, turn, natural turn of mind, bent, bias, predisposition, proneness, proclivity, propensity, propenseness, propension, propendency, vein, humor, mood, grain, mettle, sympathy, soul, heart, breast, bosom, inner man, heart's core, heart's strings, heart's blood, heart of hearts, bottom of one's heart, penetralia mentis, secret and inmost recesses of the heart, cockles of one's heart, inmost heart, inmost soul, backbone, passion, pervading spirit, ruling passion, master passion, furore, fullness of the heart, heyday of the blood, flesh and blood, flow of soul, energy, fervor, fire, force, affected, characterized, formed, molded, cast, attempered, tempered, framed, predisposed, prone, inclined, having a bias, tinctured with, imbued with, penetrated with, eaten up with, inborn, inbred, ingrained, deep-rooted, ineffaceable, inveterate, pathoscopic, congenital, dyed in the wool, implanted by nature, inherent, in the grain, affective, in one's heart, at heart, heart and soul, affection is a coal that must be cool'd else suffe.

N  courage, bravery, valor, resoluteness, boldness, spirit, daring, gallantry, intrepidity, contempt of danger, defiance of danger, derring-do, audacity, rashness, dash, defiance, confidence, self-reliance, manliness, manhood, nerve, pluck, mettle, game, heart, heart of grace, spunk, guts, face, virtue, hardihood, fortitude, intestinal fortitude, firmness, heart of oak, bottom, backbone, spine, resolution, bulldog courage, prowess, heroism, chivalry, exploit, feat, achievement, heroic deed, heroic act, bold stroke, man, man of mettle, hero, demigod, Amazon, Hector, lion, tiger, panther, bulldog, gamecock, fighting-cock, bully, fire eater, courageous, brave, valiant, valorous, gallant, intrepid, spirited, spiritful, high-spirited, high-mettled, mettlesome, plucky, manly, manful, resolute, stout, stout-hearted, iron-hearted, lion-hearted, heart of oak, Penthesilean, bold, bold-spirited, daring, audacious, fearless, dauntless, dreadless, aweless, undaunted, unappalled, undismayed, unawed, unblanched, unabashed, unalarmed, unflinching, unshrinking, unblanching, unapprehensive, confident, self-reliant, bold as a lion, bold as brass, enterprising, adventurous, venturous, venturesome, dashing, chivalrous, soldierly, heroic, fierce, savage, pugnacious, strong-minded, hardy, doughty, firm, determined, dogged, indomitable, up to, up to the scratch, upon one's mettle, reassured, unfeared, undreaded, one's blood being up, courage sans peur, fortes fortuna adjuvat, have I not in my time heard lions roar, I dare do all that may become a man, male vincetis sed vincite, omne solum forti patria, self-trust is the essence of heroism, stimulos dedit oemula virtus, strong and great, a hero, teloque animus proestantior omni, there, is always safety in valor, virtus ariete fortier.

N  interiority, inside, interior, interspace, subsoil, substratum, intrados, contents, substance, pith, marrow, backbone, heart, bosom, breast, abdomen, vitals, viscera, entrails, bowels, belly, intestines, guts, chitterings, womb, lap, penetralia, recesses, innermost recesses, cave, interior, internal, inner, inside, inward, intraregarding, inmost, innermost, deep seated, gut, intestine, intestinal, inland, subcutaneous, abdominal, coeliac, endomorphic, interstitial, inwrought, inclosed, home, domestic, indoor, intramural, vernacular, endemic, internally, inwards, within, in, inly, here in, there in, where in, ab intra, withinside, in doors, within doors, at home, in the bosom of one's family.

N  centrality, centricalness, center, middle, focus, core, kernel, nucleus, nucleolus, heart, pole axis, bull's eye, nave, navel, umbilicus, backbone, marrow, pith, vertebra, vertebral column, hotbed, concentration, centralization, symmetry, center of gravity, center of pressure, center of percussion, center of oscillation, center of buoyancy, metacenter, central, centrical, middle, azygous, axial, focal, umbilical, concentric, middlemost, rachidian, spinal, vertebral, middle, midst, centrally.

N  love, fondness, liking, inclination, regard, dilection, admiration, fancy, affection, sympathy, fellow-feeling, tenderness, heart, brotherly love, benevolence, attachment, yearning, eros, tender passion, amour, gyneolatry, gallantry, passion, flame, devotion, fervor, enthusiasm, transport of love, rapture, enchantment, infatuation, adoration, idolatry, Cupid, Venus, myrtle, true lover's knot, love token, love suit, love affair, love tale, love story, the, old story, plighted love, courtship, amourette, free love, maternal love, storge, parental love, young love, puppy love, attractiveness, popularity, favorite, lover, suitor, follower, admirer, adorer, wooer, amoret, beau, sweetheart, inamorato, swain, young man, flame, love, truelove, leman, Lothario, gallant, paramour, amoroso, cavaliere servente, captive, cicisbeo, caro sposo, inamorata, ladylove, idol, darling, duck, Dulcinea, angel, goddess, cara sposa, betrothed, affianced, fiancee, flirt, coquette, amorette, pair of turtledoves, abode of love, agapemone, loving, fond of, taken with, struck with, smitten, bitten, attached to, wedded to, enamored, charmed, in love, love-sick, over head and ears in love, head over heels in love, affectionate, tender, sweet upon, sympathetic, loving, amorous, amatory, fond, erotic, uxorious, ardent, passionate, rapturous, devoted, motherly, loved, beloved well beloved, dearly beloved, dear, precious, darling, pet, little, favorite, popular, congenial, after one's mind, after one's taste, after one's fancy, after one's own heart, to one's mind, to one's taste, to one's fancy, to one's own heart, in one's good graces, dear as the apple of one's eye, nearest to one's heart, lovable, adorable, lovely, sweet, attractive, seductive, winning, charming, engaging, interesting, enchanting, captivating, fascinating, bewitching, amiable, like an angel, amantes amentes, credula res amor est, militat omnis amasius, love conquers all, omnia vincit amor, si vis amari ama, the sweetest joy, the wildest woe.

N  intellect, mind, understanding, reason, thinking principle, rationality, cogitative faculties, cognitive faculties, discursive faculties, reasoning faculties, intellectual faculties, faculties, senses, consciousness, observation, percipience, intelligence, intellection, intuition, association of ideas, instinct, conception, judgment, wits, parts, capacity, intellectuality, genius, brains, cognitive powers, intellectual powers, wit, ability, wisdom, Vernunft, Verstand, soul, spirit, ghost, inner man, heart, breast, bosom, penetralia mentis, divina particula aurae, heart's core, the Absolute, psyche, subliminal consciousness, supreme principle, brain, organ of thought, seat of thought, sensorium, sensory, head, headpiece, pate, noddle, noggin, skull, scull, pericranium, cerebrum, cranium, brainpan, sconce, upper story, central processing unit, CPU, arithmetic and logical unit, ALU, metaphysics, psychics, psychology, ideology, mental philosophy, moral philosophy, philosophy of the mind, pneumatology, phrenology, craniology, cranioscopy, ideality, idealism, transcendentalism, spiritualism, immateriality, universal concept, universal conception, metaphysician, psychologist, intellectual, mental, rational, subjective, metaphysical, nooscopic, spiritual, ghostly, psychical, psychological, cerebral, animastic, brainy, hyperphysical, superphysical, subconscious, subliminal, immaterial, endowed with reason, in petto, ens rationis, frons est animi janua, locos y ninos dicen la verdad, mens sola loco non exulat, my mind is my kingdom, stern men with empires in their brains, the mind, the music breathing from her face, thou living ray of intellectual Fire.

artichoke heart, artificial heart, at heart, athlete's heart, atrium of the heart, biauriculate heart, bleeding heart, break someone's heart, broken heart, bullock heart, bullock's heart, bullock's heart tree, by heart, change of heart, cockles of the heart, congenital heart defect, congestive heart failure, enlarged heart, from the heart, heart and soul, heart attack, heart block, heart cherry, heart condition, heart disease, heart failure, heart line, heart massage, heart monitor, heart murmur, heart muscle, heart of dixie, heart of gold, heart pea, heart rate, heart rhythm, heart specialist, heart surgeon, heart surgery, heart urchin, heart valve, heart ventricle, heart warming, heavy heart, jarvik artificial heart, jarvik heart, left atrium of the heart, line of heart, lose heart, order of the purple heart, purple heart, rheumatic heart disease, right atrium of the heart, take heart, take to heart, valvular heart disease