What does Dimitrios mean?
Greek Demetrios, meaning 'follower/devotee of Demeter', the goddess of grain, agriculture and the earth (her name combining a word for 'earth/mother' with 'meter', mother).
What does Nikolaos mean?
Greek Nikolaos (Nicholas), from 'nike' ('victory') and 'laos' ('people'), i.e. 'victory of the people'. Borne by Saint Nicholas.