gno·mon (nōmŏn′, -mən)
1. An object, such as the style of a sundial, that projects a shadow used as an indicator.
2. The geometric figure that remains after a parallelogram has been removed from a similar but larger parallelogram with which it shares a corner.
[Latingnōmōn, fromGreek, interpreter, pointer of a sundial, fromgignōskein, to know; see gnō- in the Appendix of Indo-European roots.]
(click for a larger image)
(click for a larger image)gnomon
top: on a sundial
bottom: A gnomon of the parallelogram ABCD is the shaded figure HBCDKL.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.