testing electrical continuity

[jeroen79]

How exactly is electrical continuity defined?

Ideally I would say 0 ? but .1 ? can be considered continuous as well.
Even 1 k? and 1 M? conduct current but I wouldn't consider them 'continous'.
And if you increase the voltage enough things like diodes will suddenly conduct.

What definition should I use when designing a continuitytester?
Resistance less than x ?? Test below y V?

[RobertHolcombe]

Continuity implies that there is a continuous path (circuit) for current to flow - the resistance threshold would depend on the DUT. General purpose continuity testers are aimed at testing relatively low resistance because the general use case is testing interconnects

[AlfBaz]

I would put it this way
Continuity is the resistive point below which, the circuit does not impede it's intended function.

For example, power earth continuity would be defined as a resistance where the fault current would not create a hazardous potential difference between the fault and ground.

Electrical continuity would be a resistance that at a certain current would not create a significant voltage drop between the source and the load or a resistance that would not dissipate enough power to cause harm to the medium carrying that current

In other words, it depends...