studio vs studio apartment

studio and studio apartment both are nouns.

Word	Noun	Adjective	Verb	Adverb
studio	Yes	No	No	No
studio apartment	Yes	No	No	No

As nouns, studio and studio apartment are synonyms defined as:

studio and studio apartment: an apartment with a living space and a bathroom and a small kitchen

studio (noun)	studio apartment (noun)
workplace for the teaching or practice of an art	an apartment with a living space and a bathroom and a small kitchen
an apartment with a living space and a bathroom and a small kitchen
workplace consisting of a room or building where movies or television shows or radio programs are produced and recorded