An instrument for measuring temperature.

तापमान मापने वाला यंत्र

English Usage: The doctor checked the patient's temperature with a thermometer.

Hindi Usage: डॉक्टर ने रोगी का तापमान थर्मामीटर से मापा।

Not commonly used as a verb, but to "thermometer" could metaphorically mean to measure or gauge something carefully.

मापना

English Usage: We need to thermometer the situation before making a decision.

Hindi Usage: हमें निर्णय लेने से पहले स्थिति को मापना चाहिए।