dilater
/ˈdaɪleɪtər/
noun
- A person or thing that dilates something, especially a medical instrument used to widen a passage or opening in the body.
- The nurse handed the doctor a dilater to gently open the patient's tear duct.
- The physical therapist recommended using a dilater to help stretch the muscle.
- A dilater is often used in dental procedures to keep the mouth open.