terrestrial vs tellurian

terrestrial is not a noun while tellurian is a noun.

Word	Noun	Adjective	Verb	Adverb
terrestrial	No	Yes	No	No
tellurian	Yes	Yes	No	No

As adjectives, terrestrial and tellurian are synonyms defined as:

terrestrial and tellurian: of or relating to or inhabiting the land as opposed to the sea or air

Other synonyms of terrestrial include telluric, terrene.

terrestrial (noun)	tellurian (noun)
	an inhabitant of the earth

terrestrial (adjective)	tellurian (adjective)
operating or living or growing on land	of or relating to or inhabiting the land as opposed to the sea or air
of or relating to or inhabiting the land as opposed to the sea or air
of or relating to or characteristic of the planet Earth or its inhabitants
of this earth
concerned with the world or worldly matters