S: (n) aqualung, Aqua-Lung, scuba (a device (trade name Aqua-Lung) that lets divers breathe under water; scuba is an acronym for self-contained underwater breathing apparatus)
S: (n) oxygen mask (a breathing device that is placed over the mouth and nose; supplies oxygen from an attached storage tank)
S: (n) respirator, inhalator (a breathing device for administering long-term artificial respiration)
S: (n) resuscitator (a breathing apparatus used for resuscitation by forcing oxygen into the lungs of a person who has undergone asphyxia or arrest of respiration)
S: (n) snorkel (breathing device consisting of a bent tube fitting into a swimmer's mouth and extending above the surface; allows swimmer to breathe while face down in the water)