What does the 'indeterminate' mean in ProgressDialog?

Maybe my English is poor but I really cannot figure out what the "indeterminate" means in this context:

Android Development → ProgressDialog.isIndeterminate()


Solution 1:

It means the "loading amount" is not measured.

Solution 2:

From wiktionary: Indeterminate: Not accurately determined or determinable. It basically just means you're unsure how long the action will take so you cannot say for example something is 50% done.

This normally just means the progress will be displayed as a constantly moving loading bar rather than a percentage or the like.