AAAmerican Accent US

set off

Both

Sense-dependent: some meanings take an object and split, others take none. Check the sense you mean.

How to say it

Stress the particle, not the verb: set OFF. Saying “SET off” is the clearest learner tell — the verb stays light and the particle carries the beat.

The /t/ flaps. Between vowels, American /t/ and /d/ both become a quick tap, so “set off” comes out as “se-doff” — closer to a fast D than a T. Drop a pronoun in the middle and it flaps twice: “set it off” → “se-di-doff”.

2 meanings

  1. 1

    To begin a journey.

    • “We set off at dawn to beat the traffic.”
    • “They set off on foot when the bus never came.”

    Similar: depart, head out

  2. 2

    To trigger an alarm or a reaction.

    • “The smoke set off the fire alarm.”
    • “That comment set her off completely.”

    Similar: trigger, prompt

The particle logic

off

Contact is broken: something detaches, leaves, or stops.

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More SET phrasal verbs

Compare the whole family →

set up

To assemble or install something so it is ready to use.

set out

To begin something with a clear intention.

set back

To delay progress.

set aside

To reserve something for a particular purpose.

set down

To place something on a surface, or to record it in writing.

set off — meaning, examples & how to say it