Ancient cloud studies were observed in combination with other weather elements and other natural sciences. The Greek philosopher Aristotle wrote Meteorologica, a work which represented the sum of knowledge of the time about science. For the first time, precipitation and the clouds from which precipitation fell were called meteors, which originate from the Greek word meteoros. From that word came the term meteorology, the study of clouds and weather. Meteorologica was based on intuition and observation, but not on what is now considered the scientific method, it was the first known work to treat a broad range of meteorological topics.