Definition of "gnomon" [gno•mon]

• An object, such as the style of a sundial, that projects a shadow used as an indicator. (noun)
• The geometric figure that remains after a parallelogram has been removed from a similar but larger parallelogram with which it shares a corner. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Scholars have talked, indeed, of a Greek origin or of an Etruscan origin, and the technical term for the Roman surveying instrument, _groma_, has been explained as the Greek word 'gnomon', borrowed through an"
• "Nelson informed everyone that the piece sticking up was called the gnomon."
• "This particular one is called a gnomon magic square, because clusters of any four contiguous numbers add up to the same sum."