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

That’s because the spread can widen even as Treasury rates rise, so long as high-yield spreads rise even further.

From MarketWatch ● Jul. 24, 2026

“I still think it hasn’t been so long that the equity that he’s built up with the pitch count is that much compromised,” Roberts said.

From Los Angeles Times ● Jul. 22, 2026

If this primitive group split off so early, how did it survive for so long while remaining relatively unchanged?

From Science Daily ● Jul. 19, 2026

Because her endometriosis had been left untreated for so long, it had formed into frozen pelvis disease where "everything was stuck together".

From BBC ● Jul. 19, 2026

This made me feel bad, but I had been wanting a pony and a .22 so long I didn’t want to give up.

From "Summer of the Monkeys" by Wilson Rawls

Related Words

• goodbye
• send-off
• sendoff