ven·ti·la·tor 
(vĕntl-ā′tər)
(vĕntl-ā′tər)n.
1. A device that circulates fresh air and expels stale or foul air.
2. Medicine A machine that supplies oxygen or a mixture of oxygen and air, used in artificial respiration to control or assist breathing. Also called respirator.
venti·la·to′ry (vĕntl-ə-tôr′ē) adj.