noun
incense clock
A historical timekeeping device that measured time by burning incense, used in East Asia before mechanical clocks became common.
香盤時計は、香が燃える速さで時間を計る昔の道具です。
An incense clock is an old device that measures time by the speed at which incense burns.
Compound of 香盤 (こうばん, 'incense tray') and 時計 (とけい, 'clock'). The exact historical derivation is uncertain, but the term describes a clock that uses burning incense.