ishin-denshin (Japanese; Chin., yi hsin ch'uan hsin). Term meaning ‘to transmit the mind by means of the mind’. This zen phrase indicates the direct transmission of enlightenment (bodhi) from one mind to another, without resorting to verbal or written teachings. Through this transmission the student directly intuits the master's meaning.

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