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aperture

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aperture


  2  definitions  found 
 
  From  Webster's  Revised  Unabridged  Dictionary  (1913)  [web1913]: 
 
  Aperture  \Ap"er*ture\  (?;  135),  n.  [L.  apertura,  fr  aperire 
  See  {Aperient}.] 
  1.  The  act  of  opening.  [Obs.] 
 
  2.  An  opening;  an  open  space;  a  gap,  cleft,  or  chasm;  a 
  passage  perforated;  a  hole;  as  an  aperture  in  a  wall. 
 
  An  aperture  between  the  mountains.  --Gilpin. 
 
  The  back  aperture  of  the  nostrils.  --Owen. 
 
  3.  (Opt.)  The  diameter  of  the  exposed  part  of  the  object 
  glass  of  a  telescope  or  other  optical  instrument;  as  a 
  telescope  of  four-inch  aperture. 
 
  Note:  The  aperture  of  microscopes  is  often  expressed  in 
  degrees,  called  also  the  angular  aperture,  which 
  signifies  the  angular  breadth  of  the  pencil  of  light 
  which  the  instrument  transmits  from  the  object  or  point 
  viewed;  as  a  microscope  of  100[deg]  aperture. 
 
  From  WordNet  r  1.6  [wn]: 
 
  aperture 
  n  1:  controls  amount  of  light  admitted 
  2:  an  opening  in  something 
  3:  an  opening;  usually  small 




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