Atlantic time

WordReference Random House Unabridged Dictionary of American English © 2025

Atlan′tic time′. 

1. Time, Place Names See under standard time. Also called Atlan′tic Stand′ard Time′. 

• 1905–10

WordReference Random House Learner's Dictionary of American English © 2025

ˈstand•ard ˌtime, n. [countable]

1. Time the official time adopted for a country or region, with a difference of exactly one hour between one zone and the next.

WordReference Random House Unabridged Dictionary of American English © 2025

stand′ard time′, 

1. Time the civil time officially adopted for a country or region, usually the civil time of some specific meridian lying within the region. The standard time zones in the U.S.(Atlantic time, Eastern time, Central time, Mountain time, Pacific time, Yukon time, Alaska-Hawaii time, and Bering time)use the civil times of the 60th, 75th, 90th, 105th, 120th, 135th, 150th, and 165th meridians respectively, the difference of time between one zone and the next being exactly one hour. See diag. under time zone. 

• 1880–85, American.