america loves confusing terminology (like calling main courses 'entrees', a word that literally means starter) but none I find more confusing than saying 'twin bed' to refer to a single bed sized for only one person

common mistake- bed types are based on mattress origin, not intended layer-on. "King" and "Queen" size beds are not for royalty, they are royalty, more expensive since the harvesting process kills the hive (the most succulent varietal being of course the DoP California King). The non-reproductive caste mattresses are harvested either at Full size or from the brood-nursery as one of a few thousand Twins. You occasionally see a "Twin XL" but that's just marketing.