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[per-uh-skohp] /ˈpɛr əˌskoʊp/
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.
a periscopic lens.
1815-25; back formation from periscopic Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for periscope
  • They interpret the world through their own, somewhat limited, periscope.
  • No doubt, from an underground bunker with a periscope.
  • The van is equipped with a video camera and a periscope.
  • The periscope is mounted in a corner of a furnace to allow viewing of the entire field of the combustion space.
  • The system must include the ability to operate a wireless periscope system.
  • Camera focus via periscope eyepiece and real-time computer-displayed video.
  • The sophisticated vessel also has a conning tower, periscope and air conditioning system.
British Dictionary definitions for periscope


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
Word Origin
C19: from Greek periskopein to look around; see peri-, -scope
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
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Word Origin and History for periscope

viewing apparatus on a submarine, 1899, formed in English from peri- "around" + -scope "instrument for viewing." Earlier (1865) a technical term in photography. Related: Periscopic.

Online Etymology Dictionary, © 2010 Douglas Harper
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periscope in Science
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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