time-ball

الإنجليزية - الإنجليزية

تعريف time-ball في الإنجليزية الإنجليزية القاموس.

Rare spelling of time ball

a ball that slides down a staff to show a fixed time; especially at an observatory

A large wooden or metal ball that drops at a predetermined time to enable sailors to check their marine chronometers from their boats offshore