Lehman Brothers Government/Corporate Bond Index

What Does Lehman Brothers Government/Corporate Bond Index Mean?
An unmanaged market-weighted index, comprised of government and investment grade corporate debt instruments with maturities of one year or greater. The Lehman Brothers Government/Corporate Bond Index is a total return benchmark index for many bond funds.

Investopedia explains Lehman Brothers Government/Corporate Bond Index
The Government/Corporate Bond Index is a subset of the Lehman Aggregate Bond Index. Lehman determines if a bond is investment grade by its listed credit rating by Moody's. Investment grade bonds have a rating of Baa or higher on the Moody's scale. If the bond is unrated by Moody's, an S&P rating of BBB or higher will suffice. The index's measures performance by total return, which includes the capital appreciation or depreciation of the bond, combined with its coupon income as a percentage of the original investment.