Definition of Atlantic time in US English:

Atlantic time

noun

  • The standard time in a zone including the easternmost parts of mainland Canada, Puerto Rico, and the Virgin Islands.

    ('Atlantic Daylight Time''ADT') Atlantic time during daylight savings, three hours behind GMT

    ('Atlantic Standard Time''AST') standard time based on the mean solar time at the longitude 60° W, four hours behind GMT

    • ‘Official time is four hours behind Greenwich Mean Time, one hour ahead of Atlantic Standard Time.’
    • ‘Kate linked to a story this week in the Mirror that makes a case for Quebec joining the Atlantic time zone.’
    • ‘To obtain Atlantic Daylight Time, subtract 3 hours from Universal Time.’
    • ‘You'd have to schedule meeting times on Atlantic time to get these people to show up; they just don't check their e-mail.’
    • ‘The data suggests that joining the Atlantic time zone would reduce Quebec's high rates of depression.’