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

  • adj. Biology Having a hard shell or shell-like outer covering: testaceous echinoderms.
  • adj. Biology Composed of a shell or shell-like material: a testaceous operculum.
  • adj. Having the reddish-brown or brownish-yellow hue of bricks.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Pertaining to earthenware or baked clay.
  • adj. Of a reddish-yellow or brownish colour, like brick.
  • adj. Having a shell, especially one which is not articulated.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Of or pertaining to shells; consisted of a hard shell, or having a hard shell.
  • adj. Having a dull red brick color or a brownish yellow color.

from The Century Dictionary and Cyclopedia

  • Of or pertaining to shells, or testacean animals, as shell-fish; testacean.
  • Consisting of a hard continuous shell or shelly substance; shelly: thus, an oyster-shell is testaceous.
  • Having a hard shell, as oysters, clams, and snails: distinguished from crustaceous, or soft-shelled, as a lobster or crab.
  • Derived or prepared from shells of mollusks or crustaceans: as, a testaceous medicine; a pearl is of testaceous origin.
  • In botany and zoology, dull-red brick-color; brownish-yellow, or orange-yellow with much gray.

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

  • adj. relating to or possessing a testa or hard shell


From Latin testāceus, from testa, shell.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin testaceus. (Wiktionary)


  • From IV 2-10 he discusses the parts, both internal and external, of the ˜bloodless™ animals, i.e. the crustaceans, testaceous mollusks, cephalopods and insects.

    Aristotle's Biology

  • The foregoing remarks appear to apply to the case of the Mollusca, which, at a very early period, had reached a high organization and a great development of forms and species in the testaceous Cephalopoda.

    On the law which has regulated the introduction of new species

  • Crabs also slough off their old-age; this is generally allowed with regard to the soft-shelled crabs, and it is said to be the case with the testaceous kind, as for instance with the large ‘granny’ crab.

    The History of Animals

  • Of testaceous animals, on the contrary, no direct sensible evidence is as yet forthcoming to determine whether they sleep, but if the above reasoning be convincing to any one, he who follows it will admit this [viz. that they do so.]

    On Sleep and Sleeplessness

  • Now in the sea the earthy matter is present in large quantities, and consequently the testaceous animals are formed from a concretion of this kind, the earthy matter hardening round them and solidifying in the same manner as bones and horns (for these cannot be melted by fire), and the matter (or body) which contains the life being included within it.

    On the Generation of Animals

  • While in other animals the glutinous is dry, for which reason the covering of the invertebrates is testaceous or crustaceous, in the vertebrates it is rather of the nature of fat.

    On the Generation of Animals

  • Entirely pale rufo-testaceous, excepting the eyes and abdomen which are jet black; the nodes of the petiole pale, smooth, and shining.

    Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology

  • Abdomen testaceous at the base beneath; first band interrupted, having before it two testaceous spots.

    Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology

  • Thorax: the tegulæ pale rufo-testaceous, wings hyaline, the nervures ferruginous; the metathorax coarsely rugose; the articulations of the legs and the tarsi ferruginous.

    Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology

  • Head testaceous; antennæ testaceous, third joint short, conical; arista plumose; abdomen deep black; legs testaceous; femora black; wings limpid white, with three broad blackish stripes, the second emitting a branch from its outer side to the costa,

    Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology


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  • I just can't get enough colour words.

    April 14, 2008

  • "Having the reddish-brown or brownish-yellow hue of bricks." AHD

    April 13, 2008

  • The Conchologist's First Book; Or, A System of Testaceous Malacology, by Edgar Allan Poe, 1839.

    November 11, 2007