from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The spongy, porous, bony tissue between the hard outer and inner bone layers of the cranium.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The thin layer of soft, spongy or cancellate tissue between the bone plates which constitute the skull.

from the GNU version of the Collaborative International Dictionary of English

  • n. The soft, spongy, or cancellated substance between the plates of the skull.

from The Century Dictionary and Cyclopedia

  • n. In anatomy, the light spongy substance or open cancellated or reticulated structure of bone between the hard dense inner and outer tables of the cranial bones.
  • n. In botany, the parenchyma of a leaf, lying between the two epidermal surfaces. Also called meditullium.


Greek diploē, a fold, doubling, from feminine of diplous, twofold; see dwo- in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
This definition is lacking an etymology or has an incomplete etymology. You can help Wiktionary by giving it a proper etymology. (Wiktionary)



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  • Originally diploë.

    December 11, 2010

  • "The skull, he pointed out, is made up of three layers: the outer surface, the inner surface, and a layer in between called the diploe."
    —Jeff Benedict, No Bone Unturned (New York: Harper Collins, 2003), 73

    September 17, 2008