What I am going to talk about is why in Icelandic bed is translated as "rúm" when it is "seng" (or sometimes "køje") in danish and (as far as I know) other Scandinavian languages. Bare in mind that I only know Danish, so I am going on the assumption that the other languages (Swedish and Norwegian) are similar enough.
Now, you might know that learning words about the bed is confusing between Icelandic and other Scandinavian languages. This is because of similar but differently used words between the languages. Examples of this are bed (ice: rúm, dan: seng), mattress (ice: dýna, dan: seng), blanket/cover (ice: sæng, dan; dyne). This is very confusing, but the "sæng/seng" and "dýna/dyne" mix up is more understandable, as long ago beds weren't so wholesome that it was clear what you were supposed to sleep on top of and what you were supposed to sleep under. But one word that confused me to no end was the "rúm" one.
You see, in danish the word "rum" means, well, room. Learning that the English room (which is pronounced very much like "rúm") is the same didn't help my confusion. The most strange part about this is that the original meaning of the original word that all those "rúm/rum/room" examples stem from, it meaning space, is still used that way today in Icelandic. It is pronounced differently, with the bed "rúm" sounding more like it is written with two 'm' (aka rúmm), which confused me as a child (why were two different words written the same), but the fact is that these two meanings are still basically in the same word, with one meaning being space and the other being bed.
So, why was the word for space used for room in many languages but used for bed in Icelandic? The space becoming room is very understandable when you think about it, my space = my room, but in Icelandic room is "herbergi" (a word that meant basically fort or shelter). Well, I thought about it and it didn't take me too long to find the answer, knowing what I know about the history in Iceland.
You see, for a long time, most of our history in fact, Icelanders lived in buildings/houses called "torfbæir" which were these wooden houses covered in turf for insulation. These kind of buildings were made and used since the first settlers came here, but the ones that came after (the youngest and some still existing ones) were much different from the ones built by the "vikings". Most importantly, they were MUCH smaller, as wood was in shortage in Iceland during its later periods and it was also much colder then it was before (and is now) meaning that compressing the space was a way to conserve the heat. This made it so that those places were absolutely HORRIBLE to live in. They were dark, small, and not to mention totally unhygienic.
But these houses, because of the little space, had no bedrooms. Even the biggest "torfbæir" of the most riches families were still often with no personal bedroom. What they had were a kitchen, a place to keep the animals, a dinning room used only in special occasions and one that was only owned by those who could afford it, and the "baðstofa".
This "baðstofa" (and the name is very misleading, it seems to have been borrowed from something else and is one of the few Icelandic words that doesn't tell you anything of the thing it is supposed to be describing) was basically a bedroom and a living room all warped in one package, and was the most innermost, largest and warmest room in the whole "torfbær". In this room everybody slept, ate, read, knitted, played, whatever. And, as the space was so small, they did most of this on their beds. Eating, knitting, it was all done while sitting or laying in their beds. This meant that, for a long time all over Iceland, the peoples own personal space, their own "rúm", was their beds.
And with that, it became used as the word for ones bed, rather than ones room like in all the other countries with the same word. Because it was used for ones personal space more than the general usage of space inside house.
I hope that any of you found this interesting, and I am sorry if this was way too long and boring. This is my very first topic post here in unilang, and I had just went through the wondering and discovering of the why's of "rúm=bed not room" so I really wanted to share it with someone. If I was supposed to post this somewhere else then I apologise in advance.