so long

American  

interjection

Informal.

1. goodbye.

   I said so long and left.

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so long British  

1. informal farewell; goodbye

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adverb

1. slang for the time being; meanwhile

so long Idioms  

1. Good-bye, as in So long, we'll see you next week. The allusion here is puzzling; long presumably means “a long time” and perhaps the sense is “until we meet again after a long time,” but the usage has no such implication. [Colloquial; first half of 1800s]

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Etymology

Origin of so long

An Americanism dating back to 1840–50

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Example Sentences

See Examples For:

so long

But her new colleagues asked why she was spending so long in the toilet.

From BBC ● Oct. 25, 2026

Yet as it was left untreated for so long, it progressed into frozen pelvis disease and destroyed her reproductive organs, leaving her needing bladder reconstruction and a total hysterectomy.

From BBC ● Oct. 25, 2026

If the past is any guide, extreme dispersion among the index’s constituents can only continue for so long.

From MarketWatch ● Oct. 22, 2026

Because it has been around so long, security experts say that it is sometimes buried so deeply in corporate networks that some organizations don’t even realize they are using it.

From The Wall Street Journal ● Oct. 22, 2026

It took no effort to remember; he’d stared at the words for so long the night before that it seemed like they were imprinted on his eyeballs.

From "Found" by Margaret Peterson Haddix

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Related Words

• goodbye
• send-off
• sendoff

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