five periods and eight teachings
Dictionary Definition :
Definition[1]
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Five Periods and Eight Teachings
A name given to the p'an-chiao, or doctrinal classification system devised by Chih-i (538-97), the founder of the T'ien-t'ai school in China.
Source
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A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)