men·a·di·one (mĕn'ə-dī'ōn')
n.
A yellow crystalline powder, C₁₁H₈O₂, used in medicine as a vitamin K supplement.

[ME(THYL) + NA(PHTHALENE) + DI-¹ + -ONE.]

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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