@uliwitness no its super common, like they use the word "yotto"(ヨット) for yachts, even if they have a separate word for sailboat.
Laptop is "rapputoppu"(ラップトップ), bed is "beddo"(ベッド).

edit: dont know specifically about back rests though, as you said it may be about the specific type which doesnt fit with the Japanese word.