The meaning of the symbols is
upsidedown horse shoe = ohm's or resistance, this is what you are measuring
zero ohm's means there is no resistance, which is either a completed circuit like closing a switch or a short
infinite ohm's means just that infinite resistance which is an open condition
If you had a switch of some sort on the bench to test and turned it on, or closed it you would read zero ohm's, if you then turned it off or opened it you are opening the circuit and would read infinite resistance thus no current flow. There can be no current flowing with out some measurable resistance but it cannot be infinite. The amount resistance determines how much current will flow with a given amount of voltage.