1. an influential citizen, often a retired high official, whose advice is sought by government leaders.
2. any influential member of a company, group, etc., whose advice is respected.
3. Japanese Hist.any of the political leaders who retired from official office but continued to exert a strong influence in the government and who controlled the emperor's privy council, esp. in the period 1898–1914.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.