This is the 6356th most frequent Korean word.
아파트가
"아파트가" means "apartment" (subject marker 가 attached).
In this sentence, '아파트가' is used as the subject of the sentence, referring to the apartment being described.
여기 아파트가 정말 크고 멋져요.
The apartment here is really large and nice.
Here, '아파트가' contrasts apartments with houses, underlining a preference.
나는 아파트가 아닌 주택에서 살고 싶어요.
I want to live in a house, not in an apartment.
In this instance, '아파트가' acts as the subject, discussing a trend in apartment pricing.