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1570s, from medical Latin diastole, from Greek diastole "drawing asunder, dilation," from diastellein, from dia- "through, thoroughly, entirely" (see dia-) + stellein "to set in order, arrange, array, equip, make ready," from PIE *stel-yo-, suffixed form of root *stel- "to put, stand," with derivatives referring to a standing object or place (see stall (n.1)).
diastole di·as·to·le (dī-ās'tə-lē)
The normal rhythmically occurring relaxation and dilatation of the heart chambers, especially the ventricles, during which they fill with blood.
The period during the normal beating of the heart in which the chambers of the heart dilate and fill with blood. Diastole of the atria occurs before diastole of the ventricles. Compare systole.
diastolic adjective (dī'ə-stŏl'ĭk)
in the cardiac cycle, period of relaxation of the heart muscle, accompanied by the filling of the chambers with blood. Diastole is followed in the cardiac cycle by a period of contraction, or systole (q.v.), of the heart muscle. Initially both atria and ventricles are in diastole, and there is a period of rapid filling of the ventricles followed by a brief atrial systole. At the same time, there is a corresponding decrease in arterial blood pressure to its minimum (diastolic blood pressure), normally about 80 mm of mercury in humans. Ventricular diastole again occurs after the blood has been ejected (during ventricular systole) into the aorta and pulmonary artery.