eighteen schools at English => English (The Britannica Concise) Of Explained:
Divisions of Buddhism that arose in India in the three centuries after the death of the Buddha (c.483 BC). The number of schools, or sects, was probably closer to 30 than 18. The first division in the Buddhist community occurred as a result of the second council, held at Vaishali in the 4th cent. BC, where differences among disciples over the nature of the Buddha gave rise to the school known as the Mahasanghikas. Other schools included the Sthaviravadins and their offshoots (3rd cent. BC), incl. the Theravadins (see Theravada).