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(Jap; Chin., An-chü). In Chinese and Japanese Buddhism, this is a three-month period of retreat for Buddhist clerics (see monk; nun). It is usually held during the summer, but can be held in winter as well. In monasteries that observe the retreat, the clergy will not be allowed to venture out of the grounds without permission, and will be expected to spend more time on personal cultivation, meditation, copying scriptures, attending lectures, and other activities of this kind.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)