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

Example Sentences

See Examples For:

so long

"Let us not destroy in a moment of anger what we suffered so long to gain," he said.

From BBC ● Sep. 9, 2026

It wasn’t so long ago that a previous unwind sent Wall Street into a tailspin, and it could do so again.

From MarketWatch ● Sep. 8, 2026

I had a suspicion that these habits would only be maintained so long as I was on the app.

From Slate ● Sep. 6, 2026

Leprosy has been so long a part of human history that it has become associated with a bygone world.

From The Wall Street Journal ● Sep. 4, 2026

Wondering why I’m taking so long to answer.

From "The Bletchley Riddle" by Ruta Sepetys and Steve Sheinkin

Related Words

• goodbye
• send-off
• sendoff