The Patimokkha forms the core of the Vinaya Pitaka, the second division in the Tipitaka, which contains the rules Buddhist monks and nuns must live by. The meaning of the word pàtimokkha is unclear but it may mean something like ‘obligation’ or ‘binding promise.’ The original Pàtimokkha was a collection of aphorisms summarising the Buddha’s teachings but gradually this evolved into a code of behaviour; with 227 rules for monks and an extra 84 rules for nuns.