airlock vs air lock

airlock and air lock both are nouns.

Word	Noun	Adjective	Verb	Adverb
airlock	Yes	No	No	No
air lock	Yes	No	No	No

As nouns, airlock and air lock are synonyms defined as:

airlock and air lock: a chamber that provides access to space where air is under pressure

airlock (noun)	air lock (noun)
a chamber that provides access to space where air is under pressure	a chamber that provides access to space where air is under pressure