1. expanding or becoming wider, especially of an opening in the body
Usage: medical
2. speaking or writing at length about a topic
Usage: formal

Examples

• The doctor noticed her pupils were dilating in response to the dim light.
• The cervix begins dilating during labor.
• His blood vessels were dilating from the medication.
• The professor kept dilating on the importance of the discovery.
• She was dilating upon her travel experiences for hours.
• The eye drops caused his pupils to start dilating immediately.