What is another word for time-ball?
Pronunciation: [tˈa͡ɪmbˈɔːl] (IPA) 
A time-ball is an instrument used to display the time visually. It was used in the 19th century as a means of helping navigators determine their longitude. The time-ball would fall at a specific time, usually at noon, and sailors could observe it to set their chronometers. Synonyms for time-ball include a "time-globe," "time-dome," or "noon-ball." There have been numerous variations of the time-ball, and it has been used in many different locations across the globe. While the technology may seem outdated now, the time-ball played an important role in early navigation and timekeeping.
