16 CFR § 1213.2 - Definitions.
As used in this part 1213:
Bed. See Bunk bed.
Bed end structure means an upright unit at the head and foot of the bed to which the side rails attach.
Foundation means the base or support on which a mattress rests.
Guardrail means a rail or guard on a side of the upper bunk to prevent a sleeping occupant from falling or rolling out.