marathon group

noun Psychology.
  1. an encounter group that meets for an extended period of time, as eight hours to a week, in the belief that the resultant intensity and intimacy will lead to a more open expression of feelings.
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British Dictionary definitions for marathon group

marathon group

noun
  1. (in psychotherapy) an encounter group that lasts for many hours or days
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012