A doctor checking a little girls temperature using a clinical thermometer.
The definition of a clinical thermometer is a tool for measuring body temperature.
An example of a clinical thermometer is what a nurse puts in your mouth when you visit the doctor's office.
a thermometer for measuring body temperature
A thermometer used to measure body temperature, especially a small glass thermometer designed with a narrowing above the bulb so that the mercury column stays in position when the instrument is removed from the body.