Pronunciation: (tak"u-fi-lak'sis),[key] —n. 1. Med.immediate, temporary immunization against the effects of injection of a toxic extract owing to previous small injections of the same extract.
2. a decreased response to a medicine given over a period of time so that larger doses are required to produce the same response. Also,tach•y•phy•lax•i•aPronunciation: (tak"u-fi-lak'sē-u).[key]