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

One reason the mystery endured for so long was simply the rarity of inherited AnWj negative blood.

From Science Daily ● Sep. 19, 2026

Over time, some hotels allowed her to book a room or suite, so long as she used the service elevator and ate meals in her room.

From The Wall Street Journal ● Sep. 18, 2026

It found nothing wrong with the practice so long as the benefit was not offered as a quid pro quo to a particular voter.

From Salon ● Sep. 15, 2026

Some people may wonder why it took them so long to reach this point.

From MarketWatch ● Sep. 14, 2026

And so long as you and me you and I are careful, I’m going to tell you.

From "The Detective's Assistant" by Kate Hannigan

Related Words

• goodbye
• send-off
• sendoff