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

  • adj. Of, relating to, or being a surface characterized by smooth, shell-like convexities and concavities, as on fractured obsidian.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Of a type of irregular fracture having planar, concentric curves, like those on a mussel shell. Of a mineral having such a fracture, such as flint.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Having elevations or depressions in form like one half of a bivalve shell; -- applied principally to a surface produced by fracture.

from The Century Dictionary and Cyclopedia

  • In mineralogy, having convex elevations and concave depressions like shells: applied principally to such a surface produced by fracture, as exemplified in obsidian.
  • In mathematics, pertaining or relating to the conchoid: as, Holm's conchoidal screw.


From Greek konkhoeidēs, mussellike : konkho-, concho- + -oeidēs, -oid.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From conchoid (Wiktionary)



Log in or sign up to get involved in the conversation. It's quick and easy.