periscope

American  

[per-uh-skohp] / ˈpɛr əˌskoʊp /

noun

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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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

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 most expensive variant of the new generation iPhone will have a periscope camera that could improve zoom capacity by 5 times or more, according TF International Securities analyst Ming-Chi Kuo.

From Reuters • Aug. 29, 2023

The two gunners inside the periscope turret watch from beneath the rims of their helmets.

From "All the Light We Cannot See" by Anthony Doerr