respirator

n. 1 apparatus worn over the face to warm, filter, or purify inhaled air. 2 apparatus for maintaining artificial respiration.

n. A divice of gauze or wire, covering the mouth or nose, to prevent the inhalation of noxious substances, as dust or smoke. Being warmed by the breath, it tempers cold air passing through it, and may also be used for the inhalation of medicated vapors.