Di*as"to*le (?), n. [L., fr. Gr. , fr. to put asunder, to separate; through + to set, to place.]
1. Physiol.
The rhythmical expansion or dilatation of the heart and arteries; -- correlative to systole, or contraction.
2. Gram.
A figure by which a syllable naturally short is made long.
© Webster 1913.