periscope

American  

[per-uh-skohp] / ˈpɛr əˌskoʊp /

noun

periscopes plural

1. an optical instrument for viewing objects that are above the level of direct sight or in an otherwise obstructed field of vision, consisting essentially of a tube with an arrangement of prisms or mirrors and, usually, lenses: used especially in submarines.

2. a periscopic lens.

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periscope British  

/ ˈpɛrɪˌskəʊp /

noun

1. any of a number of optical instruments that enable the user to view objects that are not in the direct line of vision, such as one in a submarine for looking above the surface of the water. They have a system of mirrors or prisms to reflect the light and often contain focusing lenses

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periscope Scientific  

/ pĕr′ĭ-skōp′ /

1. An instrument that has angled mirrors or prisms and allows objects not in the direct line of sight to be seen, often used on submarines and in military reconnaissance.

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Other Word Forms

Noun Inflected Forms

• periscopes
  plural

Etymology

Origin of periscope

First recorded in 1815–25; back formation from periscopic

Explanation

A periscope is a tool you use to see things that would otherwise be hidden or obstructed. If you've ever been stuck in a submarine, curious about what's going on above water, then you've needed a periscope. You may have heard -scope used with other words that have to do with seeing things, as it means "a viewing instrument." You use a telescope to look at stars and a microscope to look at teeny, tiny cells. A periscope is a tool that helps you see around what is an otherwise blocked view. It's often shaped like an "L" and can help you keep an eye on when your teacher will be rounding the corner!

Example Sentences

See Examples For:

periscope periscopes

The periscope device never made it to production but the distinctive roof profile survived, earning the cars the nickname “Periscopio.”

From The Wall Street Journal ● Apr. 25, 2026

Washington afterwards released what it said was periscope footage of the submarine firing on the ship, and an image of its hull almost vertical as it slipped below the surface.

From Barron's ● Mar. 6, 2026

In his metaphorical submarine without a periscope, the attorney general and his senior staff were oblivious to what was occurring on Capitol Hill just a few blocks from the Justice Department building.

From Salon ● Apr. 6, 2024

The Normandie crew spotted its periscope poking through the waves and sprang into action.

From Seattle Times ● Mar. 9, 2024

A hand emerged, like a submarine periscope breaking surface, and dropped.

From "A Thousand Splendid Suns" by Khaled Hosseini

You can sit at the controls and peer through periscopes in a submarine room removed from attack submarine USS Greenling.

From Seattle Times ● Feb. 14, 2024

The order will see Thales Glasgow continue a 100-year tradition of making periscopes for Royal Navy submarines.

From BBC ● Jul. 13, 2023

“And they’re able to see periscopes or other changes in the water that can point to a submarine.”

From New York Times ● Feb. 3, 2023

Still on the forbidden list: Phones, firearms, running, tipping, wearing baseball caps backward, ladders, periscopes and calling fans anything other than “patrons.”

From Washington Times ● Apr. 9, 2016

Little water snakes slipped down to the rocks and then gently entered the water and swam along through the pool, their heads held up like little periscopes and a tiny wake spreading behind them.

From "Cannery Row" by John Steinbeck