Sentence:  For purposes of this chapter, a mobility device is a manual wheelchair, power wheelchair, power-operated vehicle (scooter), or <WSD>wheelbench</WSD> (a device, similar in function to a wheelchair, that is used by a person in a recumbent position). 
Meaning of the word marked with <WSD> tags:  A manually propelled, wheeled mobility device in which the user lies down. The user pushes the wheels with the hands in a similar way to propelling a wheelchair or, alternatively, a second person pulls or pushes it by the handles.