atomic clock

English Thesaurus

1. a timepiece that derives its time scale from the vibration of atoms or molecules (noun.artifact)

hypernym	:	horologe, timekeeper, timepiece,
definition	:	a measuring instrument or device for keeping time (noun.artifact)

hyponym	:	ammonia clock,
definition	:	an atomic clock based on vibrational frequency of the nitrogen atom in the ammonia molecule (noun.artifact)

hyponym	:	caesium clock,
definition	:	an atomic clock based on the energy difference between two states of the caesium nucleus in a magnetic field (noun.artifact)