international atomic time

noun
1.
a system of measuring time based on atomic clocks that measure the second as the basic unit of time in the International System of Units (SI).
Abbreviation: IAT.
British Dictionary definitions for international atomic time

International Atomic Time

noun
1.
the scientific standard of time based on the SI unit, the second, used by means of atomic clocks and satellites to synchronize the time standards of the major nations TAI
Contemporary definitions for international atomic time
noun

See atomic time

international atomic time in Technology
time, standard
(TAI) An international standard measurement of time based on the comparison of many atomic clocks. TAI is maintained by the Bureau International des Poids et Mesures (BIPM), the world's governing body for civil atomic time measurement. TAI is the basis for Coordinated Universal Time.
BIPM (https://bipm.fr/enus/5_Scientific/c_time/time_1.html).
(2001-08-02)