But the contraction and dilation of her pupils were so swift that no one but an expectant observer would have noted the change.
White is produced by the dilation, black by the contraction, of the particles of sight.
With what a dilation of spirit the ladies would have told tales of him, Fionn's father.
Thank Heaven, there is yet no dilation of the pupil; it is not too late!
But the violet of her eyes was all but hidden by the dilation of her pupils.
After all, the colony would be but "an extension or dilation of the realm of England."
This I attributed to the dilation of the air contained in the cellular tissue of the organ as much as to the cold outside.
Systole and diastole, the contraction and dilation of the heart and arteries.
The dilation of the air, by virtue of its elastic force, is found to be very surprising.
He believed very thoroughly in drainage, and in the dilation of narrow fistulous openings.
dilation di·la·tion (dī-lā'shən, dĭ-)
The act of expanding or the condition of being expanded.