A clinical thermometer is a medical device used to measure body temperature. It helps healthcare professionals and individuals determine if someone has a fever or if their temperature is within a normal range. Clinical thermometers can be digital or mercury-based, with digital versions being more common today due to safety and ease of use. These thermometers are typically used in various settings, including hospitals, clinics, and homes. They can be placed under the tongue, in the armpit, or rectally, depending on the method chosen. Accurate temperature readings are essential for diagnosing illnesses and monitoring health conditions.