Demos
Demos means people and could mean either citizens or the common people as a whole. The popular assembly would be representative of the demos. It's also a name for the subsection of a polis.
hierodoulos, pl. hierodouloi
They were ' temple slaves'. They were either the property of a temple but not involved in sacrifices, donations as slaves to the temple( mainly for cultic purposes) or slaves who received complete or partial freedom by being transferred to a deity ( they were freed by the gods).
Delphi
Was a city, territory and sanctuary. Its geography meant it was well linked to the rest of Greece in terms of accessibility. For example, the harbour of Cirrha made it easily accessible to travellers coming from Isthmus, the Peloponnese and the west.
It was also home to the sanctuary of Apollo. It contained physical goods obtained through offerings , spoils of war and pelanos ( a tax you had to pay for using the oracle). There were constant disputes on territorial claims. It established itself as a panhellenic cult after 590 BC