Das Zimmer is one of the two main German words for a room. The other one is der Raum, but at least if you talk about rooms of an apartment, Zimmer is the word of choice.
- Meine Wohnung hat ein Schlafzimmer und ein Wohnzimmer.
- My apartment has a bedroom and a living room.
And Zimmer actually has a surprising cousin in English: timber.
Originally, the words were used for wood you build houses with as well as for the building itself. And German and English simply focused on different aspects of the word.
By the way… it’s very likely that they actually come from the same Indo-European root as the Latin word domus (house, home), which makes them relatives to words like domestic, danger, madame, dominate and dungeon.