respirator vs ventilator

respirator and ventilator both are nouns.

Word	Noun	Adjective	Verb	Adverb
respirator	Yes	No	No	No
ventilator	Yes	No	No	No

As nouns, ventilator is a hypernym of respirator; that is, ventilator is a word with a broader meaning than respirator:

respirator: a breathing device for administering long-term artificial respiration
ventilator: a device that facilitates breathing in cases of respiratory failure

Other hypernyms of respirator include breathing apparatus, breathing device, breathing machine.

respirator (noun)	ventilator (noun)
a breathing device for administering long-term artificial respiration	a device (such as a fan) that introduces fresh air or expels foul air
a protective mask with a filter; protects the face and lungs against poisonous gases	a device that facilitates breathing in cases of respiratory failure