na-adjective
Formal or literary term describing buildings, structures, or scenery that are large and impressive.
そのホテルは広壮なロビーで知られている。
The hotel is known for its grand lobby.
山の上に広壮な城がそびえている。
A magnificent castle towers on top of the mountain.
Compound of 広 (wide, spacious) and 壮 (grand, robust). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning of spacious grandeur.