1911 Encyclopædia Britannica/Room

ROOM, originally a word meaning space or accommodation; the ordinary meaning of an apartment in a building, one of the interior divisions of a house, dates from the 15th century. The word is common to Teutonic languages, cf. Du. ruim, Ger. Raum, Swed. and Dan. rum, with the original meaning of space. Skeat connects the word with the root seen in Lat. rus, open country.