das Rathaus, ¨-er

Meaning (in English)

Rathaus means town hall / city hall: the main administrative building of a municipality where the local government (mayor’s office, civil registry, council administration, etc.) is based.
Depending on the size of the place, it can refer to the town hall (smaller place) or city hall (larger city), but in German the same word is used for both.

Word parts (etymology / composition)

• Rat = council (historically also “advice” or the body of councillors)
• Haus = house/building
  So Rathaus literally means “council house”, i.e., the building of the municipal council/administration.

German synonyms

• Stadthaus (regional/less common; can overlap with city administration building)
• Stadtverwaltung (often the administration as an institution; sometimes used for the offices/building)
• Gemeindehaus / Gemeindeamt (more common for smaller municipalities; “municipal office”)
• Verwaltungsgebäude (generic: administrative building)

German antonyms (if applicable)

There is no strict direct antonym, but related “opposites” by context could be:

• Privathaus (private house, not a public/government building)
• Wohnhaus (residential building)