Bumping this. Any insight into my question above?
If your savings is higher than the Federeal Deposit Insurance Sceme VMFXX is safer than a savings account at a bank. This is as safe and defensive as you can get. The only comparable alternative will be buying t-bills outright.
As for terminology for goverment securities:
Bills: Maturity 4,8,13,17,26 or 52 weeks
Notes: Maturity 2,3,5,7 or 10y
Bonds: Maturity 20y or 30y.