Definition of "dihedral" []

• Mathematics Formed by or having two plane faces; two-sided. (adjective)
• Mathematics Relating to, having, or forming a dihedral angle. (adjective)
• Mathematics A dihedral angle. (noun)
• Mathematics A dihedral group. (noun)
• Aeronautics The upward or downward inclination of an aircraft wing from true horizontal. (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.

• "Swedish manufacturer Koenigsegg is also taking door design to a new level with what it calls the dihedral synchro-helix actuation system."
• "The angle between two planes is termed dihedral, between three trihedral, between any number more than three polyhedral."
• "The silhouettes of eagles flatten out, while the wings of vultures show a dihedral curve (bird guides love throwing in words such as "dihedral," forcing you to not only look up birds but words as well)."