noun
a timepiece that derives its time scale from the vibration of atoms or molecules
• Hypernyms: ↑timepiece, ↑timekeeper, ↑horologe
• Hyponyms: ↑ammonia clock, ↑caesium clock
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noun, pl ⋯ clocks [count]
: a special kind of clock that is extremely exact
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an extremely accurate clock that uses the movement of atoms or ↑molecules to measure time
Useful english dictionary. 2012.