from The Century Dictionary.

  • Pertaining to a pyramid, or having its form. Also pyramidical.
  • In bot., anat., and zoology, shaped more or less like a pyramid; conical; pyriform.
  • In anatomy, noting a muscle whose fibers arise from a long base and converge to the point of their insertion: correlative with prismatic, 3, and rhomboidal, 2.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Of or pertaining to a pyramid; in the form of a a pyramid; pyramidical.
  • adjective (Crystallog.) Same as Tetragonal.
  • adjective (Math.) certain series of figurate numbers expressing the number of balls or points that may be arranged in the form of pyramids. Thus 1, 4, 10, 20, 35, etc., are triangular pyramidal numbers; and 1, 5, 14, 30, 55, etc., are square pyramidal numbers.
  • noun (Anat.) One of the carpal bones. See cuneiform, n., 2 (b).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective geometry Pyramid-shaped.
  • noun anatomy One of the carpal bones.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective resembling a pyramid


from Wiktionary, Creative Commons Attribution/Share-Alike License

From medieval Latin pyramidalis


  • We loved the presentation on the rice in pyramidal form.

    NJ Dining: Little Charm

  • It is often called the pyramidal or fastigiate poplar.

    Species and Varieties, Their Origin by Mutation

  • These are called pyramidal cells (from their shape), or Betz cells (after the Russian anatomist Vladimir Betz, who first described them in 1874).

    The Human Brain

  • The fibers from the motor area form into a bundle called the pyramidal tract, or pyramidal system.

    The Human Brain

  • A third lobe, of conical shape, called the pyramidal lobe, frequently arises from the upper part of the isthmus, or from the adjacent portion of either lobe, but most commonly the left, and ascends as far as the hyoid bone.

    XI. Splanchnology. 4. The Ductless Glands

  • When these pyramidal fibers are traced downward it is found that some two-thirds or more of them leave the pyramids in successive bundles, and decussate in the anterior median fissure, forming what is termed the pyramidal decussation.

    IX. Neurology. 4a. The Hind-brain or Rhombencephalon

  • They are ordinarily called pyramidal or fastigiate forms, and as far as their history goes, they arise suddenly in large sowings of the normal species.

    Species and Varieties, Their Origin by Mutation

  • The same want was met in Yucatan and Chiapas by a new expedient namely a pyramidal platform or elevation of earth twenty, thirty and forty feet high upon the level summits of which their great houses were erected.

    Houses and House-Life of the American Aborigines

  • Scottish ell -- as in recent times the divine origin of the so-called pyramidal cubit and inch -- was pleaded rather strenuously.

    Archaeological Essays, Vol. 1

  • Most of the neurons within a column, and therefore within the cortex as a whole, are so-called pyramidal neurons, whose output excites the cell it synapses with.

    PLoS Biology: New Articles


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