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

Still, as Barron’s argued in our recent stock pick, Nvidia looks relatively cheap and so long as AI spending continues to increase it should be a major beneficiary.

From Barron's • Jun. 3, 2026

Jefferson believes the reason she stayed so long was because of the people she worked with, and so many of the lovely customers she got to speak to on a regular basis.

From BBC • May 31, 2026

His mother, he says, deals with self-esteem issues because her identity has for so long been reduced to being a caretaker for elderly relatives, who, inevitably, pass away — leaving her feeling like a failure.

From Los Angeles Times • May 29, 2026

Activists who have spent several years behind bars in Cuba say being imprisoned for so long leaves a permanent scar.

From The Wall Street Journal • May 29, 2026

In the meantime, I will revel in this water that was for so long my enemy.

From "Flying Through Water" by Mamle Wolo

Related Words

• goodbye
• send-off
• sendoff