Synonyms

so long

American

interjection

Informal.

goodbye.

I said so long and left.

so long British

informal farewell; goodbye

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adverb

slang for the time being; meanwhile

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

so long Idioms

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]

Etymology

Origin of so long

An Americanism dating back to 1840–50

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The administration can keep stalling an update of risk scores, but only for so long.

From The Wall Street Journal • Apr. 17, 2026

It feels so long ago that you forget, but that’s so awesome to hear because it was a lot of fun.

From Los Angeles Times • Apr. 16, 2026

“At this point, we assume a headwind to consumption, inflation and Fed rate considerations, probably manageable so long as the current cease-fire trends to a wind down of hostilities over the next several weeks.”

From MarketWatch • Apr. 14, 2026

And was he, after operating for so long without getting caught, perhaps even wearing a badge?

From BBC • Apr. 10, 2026

It’s been so long since I’ve had it.

From "Red Flags and Butterflies" by Sheryl Azzam

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023