Internal temperature refers to the measure of heat within an object or a system. It is typically measured using a thermometer and indicates the degree of hotness or coldness of something, depending on whether it's above or below the standard body temperature of 98.6°F (37°C). Internal temperature can be used to describe the heat within living organisms such as humans, animals, or plants, but also in non-living systems like machines and chemical reactions. It is an important factor that influences the rate of a reaction, efficiency of a machine, and overall health and wellbeing of living creatures.