Heliometry refers to the measurement of the Sun's distance from Earth and its diameter. Synonyms for heliometry include astrometry, the branch of astronomy that deals with the measurement of the position and movements of celestial bodies; photometry, the measurement of the intensity of light emitted or reflected by a celestial body; and spectrophotometry, the measurement of the intensity and color of light emitted or absorbed by a celestial body. Other synonyms for heliometry include solarometry and solenometry, both of which relate specifically to the measurement of the Sun. These terms are important in the study of astronomy, helping researchers to better understand the properties and behavior of our nearest star.