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grid variation

American  

noun

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  1. the angle, at any point on the surface of the earth, between the magnetic and true meridians passing through that point.


grid variation British  

noun

  1. Also called: grivationnautical the angle between grid north and magnetic north at a point on a map or chart

"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