also: くろう
noun
drum tower; temple drum tower
A tower in a Buddhist temple complex that houses a drum used to mark the time. The reading ころう is standard; くろう is less common.
この寺の鼓楼は江戸時代に建てられた。
The drum tower of this temple was built in the Edo period.
鼓楼の太鼓が時を告げる。
The drum in the drum tower announces the time.
鐘楼 is a bell tower, while 鼓楼 is specifically a drum tower.
From Chinese 鼓樓／鼓楼 (gǔlóu), literally 'drum tower'. The reading ころう is the go-on reading; くろう is the kan-on reading.