second heart sound

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sec·ond heart sound (S2),

the second sound heard on auscultation of the heart; signifies the beginning of diastole and is due to closure of the semilunar valves.
Synonym(s): second sound

second heart sound

Cardiology A heart sound that corresponds to closure of the semilunar–pulmonary and aortic valves, which is a short, higher pitched “dubb”. See First heart sound, Fourth heart sound, Third heart sound.

sec·ond heart sound

(S2) (sek'ŏnd hahrt sownd)
The second sound heard on auscultation of the heart; signifies the beginning of diastole and is due to closure of the semilunar valves; auscultated at base of heart.
References in classic literature ?
There had been at one moment a slight murmur in the drawing-room at Mansfield Park about sending her a prayer-book; but no second sound had been heard of such a purpose.
My mind was made up in an instant, and I was at the top of the strong-room stairs, the knocking still continuing, when a second sound drove me back.
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But because few other English words ended in the consonant cluster \kth\, the second sound lost its fricative quality and became a simple \t\, remaining so even after the \k\ sound had been lost.
a memory-type thermoelastic system of second sound associated with homogeneous Dirichlet boundary conditions and initial data in suitable function spaces.
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MY second sound like I should be sitting under a pyramid but my mind is a busy one.
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The force hurled a second sound bomb and began to advance.