Dictionary.net

a mask with a filter protects the face and lungs against poisonous gases

a breathing device for administering long-term artificial respiration

a breathing device for administering long-term artificial respiration

a protective mask with a filter; protects the face and lungs against poisonous gases

Mechanical devices used to produce or assist pulmonary ventilation.

A helmet of cloth or other material, usually chemically treated, worn in the World War as a protection against poison gas; used also in certain medical treatments.

An appliance fitting over the mouth and nose, used for the purpose of excluding dust, smoke, etc., or of warming the air before it enters the respiratory passages.

Instrument to eliminate impurities from inspired air.

A contrivance of network which covers the mouth, and protects the lungs from the sudden inspiration of cold air.

Same etymon. Various instruments, under this name, have been devised for the purpose of tempering the air before it reaches the lungs in winter. One of the best is that of Jeffrey, which is made of several layers of fine wire tissue.

Apparatus to qualify the air that is breathed through it.

An apparatus to be fitted over the mouth, or over the mouth and nose, for modifying the inspired air or filtering it from impurities.

n. An instrument covering the mouth through which persons of weak lungs can breathe without injury.