jet lag
Jet lag (noun) means the tiredness, disturbed sleep, and general disorientation felt after flying quickly across several time zones, caused by the body's internal clock being out of step with local time. Example: “I had terrible jet lag for three days after landing in Tokyo.”
How to Use Jet lag
Learner’s notesIn plain EnglishFeeling exhausted and out of sync after a long flight across time zones.
Neutral and universal. Usually two words in British English, sometimes hyphenated as an adjective (jet-lagged).
Jet lag is uncountable: say "I have jet lag", not "a jet lag". The adjective is jet-lagged.
Trace the full origin ↓Fill the Gap
Can you complete this real example?
I had terrible _____ for three days after landing in Tokyo.
Etymology
A compound of jet, the aircraft, and lag, meaning a delay — the body's clock lagging behind local time after fast air travel.
Synonyms
View more →Frequently Asked Questions
What is the difference between jet lag and travel fatigue?
Travel fatigue is plain exhaustion from the journey itself — cramped seats, dry air, broken sleep — and it clears after a good night's rest. Jet lag comes specifically from crossing time zones and lasts until your body clock resets, typically about a day per time zone.
Why is jet lag worse flying east?
Flying east shortens your day and asks your body clock to run ahead, which it resists. Flying west lengthens the day, and most people's internal clock naturally drifts slightly longer than 24 hours, so it adapts more easily.
How long does jet lag last?
A common rule of thumb is roughly one day of recovery per time zone crossed, though it varies by person, direction of travel and how much daylight you get on arrival. Morning light after an eastward flight speeds the reset.