noun, noun, used as a suffix
tower; tall building; belvedere
Often used as a suffix in building names, e.g., 展望楼 (observation tower). Can refer to any tall, multi-storied structure.
城の楼から町を見下ろした。
I looked down at the town from the castle tower.
このホテルには展望楼がある。
This hotel has an observation tower.
noun, noun, used as a suffix
Specifically a tower used for observation or defense, such as a castle turret or a watchtower.
火の見楼から火事を知らせる鐘が鳴った。
The fire lookout tower bell rang to alert of a fire.
noun, noun, used as a suffix
Archaic euphemism for a brothel, derived from the multi-storied structure of such establishments in the Edo period.
江戸時代、吉原には多くの楼が立ち並んでいた。
In the Edo period, many brothels lined the streets of Yoshiwara.
塔 is a more general term for tower, often free-standing and slender, while 楼 emphasizes a multi-storied building, often part of a larger structure or used in names.
櫓 refers specifically to a turret or watchtower, often wooden and temporary, whereas 楼 can be a more permanent stone or brick structure.
From Middle Chinese 樓 (ləu). The character originally depicted a multi-storied building. The archaic 'brothel' sense developed in Japanese from the association with tall, ornate buildings in pleasure quarters.