An Etymological Dictionary of the German Language/Zimmer
Zimmer, n., ‘room, chamber,’ from MidHG. zimber, OHG. zimbar, n., ‘timber, wooden building, dwelling, room'; corresponding to OSax. timbar, Du. timmer, ‘room,’ AS. timber, E. timber, OIc. timbr. To these are allied Goth. timrjan, ‘to build up' OHG. and MidHG. zimberen, ModHG. zimmern, ‘to build.’ The primary meaning of the subst. was certainly ‘wood for building'; it is primit. allied to Lat. domus, Gr. δόμος, Sans. dama, OSlov. domŭ, ‘house' (lit. ‘building of wood'); and also to the root vb. Gr. δέμω, ‘to build' (δέμας, ‘bodily frame').