Geocentric model knew about Tusi's work or that of the Maragha school. Not all Greeks agreed with the geocentric model. The Pythagorean system has already been mentioned; some Pythagoreans believed the Earth to be one of several planets going around a central fire. Hicetas and Ecphantus, two Pythagoreans of the 5th century BC, and Heraclides Ponticus in the 4th century BC, believed that the Earth rotated on its axis but remained at the center of the universe. Such a system still qualifies as geocentric. It was revived in the Middle Ages by Jean Buridan. Heraclides Ponticus was once thought to have proposed
Umbrella term Umbrella term An umbrella term is a popular metaphorical phrase that covers a wide range of concepts belonging to a common category. For example, "cryptology" is an umbrella term that encompasses cryptography and cryptanalysis, among other fields. Similarly, an umbrella organization is a central and coordinating body representing a number of smaller, separate bodies. A blanket term is a closely related word or phrase that is used to describe multiple groups of related things. The degree of relation may vary or have a minimal relationship, but blanket terms often trade specificity for ease of use. In other words, a blanket