What is "401(k)"?

[Gray]

I recently came across this -

"This job offer comes with a 401(k)."

"401(k)" -- seems something related to the money but what is it exactly?
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First lesson - English, not english. I, not i. ~A student of English

[Milanya]

401(k)
From Wikipedia, the free encyclopedia
In the United States of America, a 401(k) plan allows a worker to save for retirement by deporting the savings invested while deferring current income taxes on the saved money and earnings until withdrawal.
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.