upside down

American  

adverb

1. with the upper part undermost.

2. in or into complete disorder; topsy-turvy.

   The burglars turned the house upside down.

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upside down British  

adjective

1. (usually postpositive; upside-down when prenominal) turned over completely; inverted

2. informal (upside-down when prenominal) confused; muddled; topsy-turvy

   an upside-down world

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adverb

1. in an inverted fashion

2. in a chaotic or crazy manner

Other Word Forms

• upside-down
  adjective
• upside-downness
  noun

Etymology

Origin of upside down

1300–50; re-formation ( see upside) of Middle English upsedoun, earlier up so doun ( see up, so ¹, down ¹; sense of so obscure)

Example Sentences

"I'm extremely curious as to why my life was turned upside down like it was," said Malkinson.

From BBC • May 19, 2026

Turn it upside down “and a billionaire falls through the ceiling,” she said.

From Los Angeles Times • May 13, 2026

So far this year, the Iran war has turned OPEC’s usual production problem upside down.

From Barron's • Apr. 28, 2026

"The results are a surprise. They turn our understanding of the evolution of the eye and the brain upside down," says Dan-E Nilsson, professor emeritus in sensory biology at Lund University.

From Science Daily • Apr. 27, 2026

As the icebergs drift, the seawater erodes them from below, until the berg abruptly topples over and continues its journey upside down.

From "Shipwreck at the Bottom of the World" by Jennifer Armstrong