Meaning & use
dilation
Last updated
Meanings
noununcountablemedical
The widening or opening up of a body part or passage, such as the pupil of the eye or the cervix.
Grammar: Usually uncountable and followed by of: dilation of the pupils.
Patterns
- dilation of something
The doctor checked the dilation of her pupils with a small light.
Dilation of the blood vessels can lower blood pressure.
Nurses measure cervical dilation during labor in centimeters.
nouncountablemathematics
In mathematics, a change that makes a shape bigger or smaller by the same scale factor without altering its form.
Grammar: Countable in geometry: a dilation by a factor of two.
Patterns
- a dilation by a factor of something
A dilation with a scale factor of three triples every side of the triangle.
The students drew a dilation of the square on graph paper.
Under a dilation, the angles stay the same.
Word forms
| plural | dilations |
|---|
Common combinations
- pupil dilation
- Pupil dilation can be a sign that someone is interested.
- cervical dilation
- Cervical dilation is monitored throughout labor.
- vascular dilation
- Some drugs work by vascular dilation.
- scale factor of the dilation
- Find the scale factor of the dilation from the diagram.
- full dilation
- The doctor waited for full dilation before the procedure.
Synonyms and how they differ
- widening
- Widening is the everyday word for becoming broader, while dilation is a precise medical or scientific term.
- expansion
- Expansion suggests growing in size overall, whereas dilation fits openings and passages that stretch wider.
- enlargement
- Enlargement can be any increase in size, including photographs, and does not point to an opening.
Opposites
Word family
Commonly confused: dilation or dilution?
dilation vs dilution
Dilution is making a liquid weaker by adding water. Dilation is making something wider.
Practice
The eye doctor used drops to cause ___ of the patient's pupils.
Choose one answer.
Dilation means widening, which is what drops do to the pupil. Dilution is weakening a liquid, which looks similar but does not fit.
Make it your own
Write a sentence using “dilation”, then check it and compare it with the examples above.