This is the 8663rd most frequent Japanese word.
新築
"Newly built" or "new construction."
Here '新築' is used as an adjective to describe a house (家) that is newly constructed.
新築の家に引っ越しました。
I moved into a newly built house.
In this sentence, '新築' serves as an adjective for an apartment (マンション), indicating that the property is recently built.
新築のマンションを購入しました。
I bought a brand-new apartment.
'新築' describes the building (ビル) as being newly constructed in this context.