No doubt "chapter and verse" definitions are available (at IEC 60601-1
et al), but from a purely practical standpoint:-
Protective Earth is provided by the "earth" conductor in the mains cable of Class I equipment (equipment mains connector to the earth pin on the mains plug).
Functional Earth is a point in equipment (usually on the chassis, and sometimes brought out as a screw or nut
etc. on the back panel) where circuit "earths" are commoned together. It may not always be apparent, but when it is it should be marked with the correct symbol.
An Equipotential Point is sometimes available (again, usually on the back panel) as a "stud" from which supplementary "earth" connections can be made within the Medical Location. It is not always provided, but when it is it will be obvious, and should also be marked with its own symbol. See this recent
thread.
I doubt that your multimeter will notice any difference between a Functional Earth and an Equipotential Point. And from either to the earth pin of the mains plug should be less than 0.2 ohms.
See
here for symbols and markings.
