VANGUARD SHORT TERM BOND INDEX FD INSTL MUTUAL FUNDS USMF - What does VANGUARD SHORT TERM BOND INDEX FD INSTL MUTUAL FUNDS USMF mean? - What does VANGUARD SHORT TERM BOND INDEX FD INSTL MUTUAL FUNDS USMF stand for? - VANGUARD SHORT TERM BOND INDEX FD INSTL MUTUAL FUNDS USMF meaning