<unk>  refers to shortness of breath (dyspnea) that is relieved when lying down, and worsens when sitting or standing up. It is the opposite of orthopnea. The word is derived from the Greek platus (= flat) and pnoia (=breath).
Platypnea
Tachypnea
Trepopnea
Apnea
Bradypnea
Hypernea
Shallow breathing
Hypopnea