a clock that measures time by monitoring (отслеживая) the resonant (звонкий) frequency (частота) of atoms.
atomic clock
a thin candle with markings (маркировки) spaced out (разбитые промежутками) that indicate how much time has passed as it burns.
candle clock
the earliest type of timekeeping device, which indicates the time of day by the position of the shadow of some object exposed to (подвергающийся воздействию)the sun's rays.
sundial
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