peculiar institution

noun

1. Black slavery in the southern U.S. before the Civil War.

Word History and Origins

Origin of peculiar institution¹

An Americanism dating back to 1835–45

Example Sentences

And this is before we consider America’s “peculiar institution”: slavery.

From Salon

But with one presidential candidate unable to identify slavery as causal to the Civil War, another claiming it was a nuisance that could have been negotiated around and books depicting the horror of the “peculiar institution” bound for bans in certain school districts, how can a mass appeal to examine painful American history not be anything but futile?

From Seattle Times

The sport may be our most peculiar institution, and if you don’t agree, please, try explaining our fall Saturday spectacle to anyone outside our borders as I have.

From Los Angeles Times

What was the war about, and what was the role of slavery, the most peculiar institution in all American history?

From Salon

That second reason is the "peculiar institution."

From Salon