heartstrings

Noun

heartstrings pl (normally plural, singular heartstring)

1. (historical, plural, plural-normally) The tendons or other structures resembling cords once thought to be attached to, or to brace, the heart; especially the aorta, pulmonary artery, and other large arteries connected to them; also, the diaphragm.
   • Harte ſtrynges uenies de cuevr.[1530 July 28 (Gregorian calendar), Iohan Palsgraue [i.e., John Palsgrave], “The Table of Substantyues”, in Lesclarcissement de la langue francoyse⸝ […], [London]: […] [Richard Pynson] fynnysshed by...
   • The Ueynes are ſpred foorth throughout the whole bodie, howbeit from one welhead, that is to ſay from the Liuer: ſo be the Sinews, howbeit from the Brayne; So likewiſe are the Heartſtrings, howbeit from the Heart.1587, Philip of Mornay [i.e., Philippe de Mornay], “That there is but Onely One God”, in Philip Sidney, Arthur Golding, transl., A Woorke Concerning the Trewnesse of the Christian Religion, […]...
2. (broadly, plural, plural-normally) Synonym of chordae tendineae (“the cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart”).
   • The atrioventricular valves are prevented from turning inside out by strands of connective tissue, which run from their underside to the walls of the ventricle. These are the so-called heartstrings or chordae tendin[e]ae.2002, “Applied Physiology A”, in Beryl Stretch, editor, BTEC National Health Studies, Oxford, Oxfordshire: Heinemann Educational Publishers, →ISBN, page 481
   • Joined to the free ends of the AV [atrioventricular] valves are a number of cords called chordae tendineae (heart strings) attaching them to muscles in the wall of the ventricle. The heart strings keep the AV flaps pointing in the direction of the blood flow, stopping them being turned "inside out"...2005, “Section 2: Heart”, in The Facts on File Illustrated Guide to the Human Body: Heart and Circulatory System, New York, N.Y.: Facts on File, →ISBN, page 40

   Synonyms:

   chordae tendineae

3. (figuratively, plural, plural-normally) The source of one's deepest emotions or inner feelings, especially compassion or love.
   • The sad eyes of the orphan tugged at my heartstrings.
   • Soone as ſhe heard the name of Artegall, / Her hart did leape, and all her hart-ſtrings tremble, / For ſudden ioy, and ſecret feare vvithall, […]1596, Edmund Spenser, “Book IV, Canto VI”, in The Faerie Queene. […], part II (books IV–VI), London: […] [Richard Field] for William Ponsonby, →OCLC, stanza 29, page 88
4. (archaic, figuratively, plural, plural-normally) The essential or vital part of something; the core, the essence, the heart.
   • And for to ſeeke out gemmes and ſome little ſtones, vve ſtrike pits deep vvithin the ground. Thus vvee plucke the very heart-ſtrings out of her [the Earth], and all to vveare on our finger one gemme or precious ſtone, to fulfill our pleaſure and deſire.1601, C[aius] Plinius Secundus [i.e., Pliny the Elder], “[Book II.] Of Earth and the Nature thereof.”, in Philemon Holland, transl., The Historie of the World. Commonly Called, The Naturall Historie...

   Synonyms:

   bowels, sum, brass tacks, core, crux, essence, gist, drift, guts, gravamen