John C. Bogle founded Vanguard, which had the first index funds. Simply put, "Boglehead" refers to someone who invests in index fund(s) and leaves the money the

John C. Bogle founded Vanguard, which had the first index funds. Simply put, "Boglehead" refers to someone who invests in index fund(s) and leaves the money there long-term, without trying to time the market, buy individual stocks, etc.