ver·tex (vûr'tĕks')
n., pl., -ti·ces (-tĭ-sēz'), also -tex·es.

1. The highest point; the apex or summit: the vertex of a mountain.
2. Anatomy.
   1. The highest point of the skull.
   2. The top of the head.
3. Astronomy. The highest point reached in the apparent motion of a celestial body.
4. Mathematics.
   1. The point at which the sides of an angle intersect.
   2. The point on a triangle or pyramid opposite to and farthest away from its base.
   3. A point on a polyhedron common to three or more sides.

[Latin, whirlpool, crown of the head (where the hair forms a whorl), vertex, from vertere, to turn.]

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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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