a breathing device for administering long-term artificial respiration
"After surviving the severe accident, John spent several months hooked up to a respirator that kept his lungs functioning while he healed."
a protective mask with a filter; protects the face and lungs against poisonous gases
"The worker put on his respirator before entering the room to ensure he was safe from the toxic fumes leaking from the pipes."
A device designed to allow breathing when it would otherwise be hindered, as by a medical condition or the presence of poisonous vapors.
"After inhaling the toxic fumes from the fire, the firefighter quickly donned his respirator before entering the burning building."