set off

Hi teachers,

He set off on a long journey. Correct?

Many thanks.

I think it should be: He set out on a long journey.

Thank you very much, THL.

So when should we use “set off”?

You can use ‘set off’ in your sentence.

It can also be used when you mean to commence a journey, but it is far less common. Though it has other meanings, ‘to set off’ is usually (mostly in banking parlance) used to mean ‘to compensate’, ‘to adjust against’ etc. Suppose you have a deposit and a loan in a bank. You have defaulted repayment of the loan. The bank can then set off your loan account by debiting your deposit account.

‘Set off’ is a phrasal verb, which is in common and popular use when speaking about the commencement of a journey.
set off:
to begin a journey
We set off for London just after ten.

Your suggestion ‘set out’ is also possible, but has slightly more emphasis on the place being left and in my experience this is less common than ‘set off’.
set out:
1 to leave a place and begin a journey
They set out on the last stage of their journey.

It also has this meaning:
2 to begin a job, task, etc. with a particular aim or goal
She set out to break the world record.
They succeeded in what they set out to do.

The banking term is ‘off-set’, not ‘set off’.