Heat stroke is a medical emergency caused by excessive heat. It can lead to dehydration, rapid heartbeat, and high body temperature, which can be fatal. There are various synonyms for the condition, including hyperthermia, thermoregulatory failure, sunstroke, heat exhaustion, and heat stress. Hyperthermia refers to an elevated body temperature, while thermoregulatory failure implies the body's inability to regulate its temperature. Sunstroke and heat exhaustion both describe the symptoms of heat stroke, while heat stress refers to the bodily response to physical exertion and hot environments. It's important to recognize the signs of heat stroke and seek medical attention immediately if symptoms occur.