Parts
From the floor up. Each part states a number, and all but one of them has to agree with a number printed on another part’s listing.
The frame
The structure the mattress rests on. Here that means metal and steel platforms, upholstered frames sold on their headboards and a solid wood platform, all stating that no box spring is needed.
Must agree with
The size name has to match the mattress. The height has nothing it must match, and the clearance under the frame is not stated.
The mattress
The layer everything else is measured from. This catalog files all-foam mattresses and a foam and spring hybrid, every one of them sold under a size name and nearly all of them under a height as well.
Must agree with
The size name has to match the frame, the topper and the cover. The height, plus any topper thickness, has to sit inside the cover’s pocket.
The topper
A layer laid on top of a mattress that states a thickness. This catalog files foam slabs that state one, and quilted pillow tops filed under the same name that do not.
Must agree with
The size name has to match the mattress. The thickness is added to the mattress height, and the cover’s pocket has to contain the sum.
The quilted cover
A quilted layer that fits over the whole mattress and holds on by a deep fitted pocket. The listings call it a pad, a protector, a cover or a topper; this site files it by the pocket it states.
Must agree with
The size name has to match the mattress. The pocket has to contain the mattress height plus any topper thickness.
The nightstand
A small table or chest beside the bed. It is filed with the bed parts, and it is the part here whose numbers nothing has to match.
Must agree with
Nothing. This part has no required match, and the page says so rather than inventing one.