1800, gooroo, from Hindi guru "teacher, priest," from Skt. guru-s "one to be honored, teacher," lit. "heavy, weighty," from PIE base *gru- (see grave (adj.)). Generalized sense of "mentor" is from 1940; sense of "expert in something" first recorded c.1966 in Canadian Eng. in ref. to Marshall McLuhan.
A leader, expert, or authority in some field, esp a charismatic or spiritual figure who attracts a devoted following: turning for guidance to such gurus as Paul Goodman and Herbert Marcuse/ That genial guru of the right, Barry Goldwater(1960s+)
A person who aids and supports someone having a psychedelic drug experience (1960s+ Narcotics & counterculture)
A computer expert: when you were with gurus (read: seasoned computer veterans)(1990s+ Computer)
[fr Sanskrit, ''venerable'']
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
guru in Technology
job An expert, especially in "Unix guru". Implies not only wizard skill but also a history of being a knowledge resource for others. Less often, used (with a qualifier) for other experts on other systems, as in "VMS guru". See source of all good bits. [Jargon File] (1996-06-01)