Physiology The normal rhythmically occurring relaxation and dilatation of the heart chambers, especially the ventricles, during which they fill with blood.
The lengthening of a normally short syllable in Greek and Latin verse.
[Greek diastolē, dilation, separation, from diastellein, to expand : dia-, apart; see dia- + stellein, to place, send; see stel- in Indo-European roots.] di'as·tol'ic (dī'ə-stŏl'ĭk) adj.