thermostat vs cryostat

thermostat and cryostat both are nouns.

Word	Noun	Adjective	Verb	Adverb
thermostat	Yes	No	Yes	No
cryostat	Yes	No	No	No

As nouns, cryostat is a hyponym of thermostat; that is, cryostat is a word with a more specific, narrower meaning than thermostat:

thermostat: a regulator for automatically regulating temperature by starting or stopping the supply of heat
cryostat: a thermostat that operates at very low temperatures

Other hyponyms of thermostat include pyrostat.

thermostat (noun)	cryostat (noun)
a regulator for automatically regulating temperature by starting or stopping the supply of heat	a thermostat that operates at very low temperatures

thermostat (verb)	cryostat (verb)
control the temperature with a thermostat