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

[From Latin testāceus, from testa, shell.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Biology) of, relating to, or possessing a test or testa
2. (Biology) of the reddish-brown colour of terra cotta
[C17: from Latin testācens, from testa]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(tɛˈsteɪ ʃəs)

1. of, pertaining to, or derived from shells.
2. having a test or shell-like covering.
3. of a brick-red, brownish red, or brownish yellow color.
[1640–50; < Latin testāceus shell-covered =test(a) (see test2) + -āceus -aceous]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.testaceous - relating to or possessing a testa or hard shell; "testaceous fish"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Diatoms and testaceous amoebae are free-living, calcareous protists 2 to 2 000 pm in size (Licea et al., 1996; Moreno et al., 1997).
1) length 5.0 mm, width 1.4-1.5 mm; integument brown-yellow (testaceous to brunneotestaceous), with infuscate head; pronotum with variable infuscate markings: median vitta, transverse anterior margin, lateral maculae posterior of midlength to mostly infuscate with hind angles testaceous; elytra variably colored brunneous to light infuscate entirely or with subapical transverse band between testaceous midlength and subapical streaks or maculae.
Antennae dark brown; legs red testaceous; all coxae black; hind leg with upper trochanter, femora at extreme apices, apical third of tibia, and tarsi fuscous; basal ventrites of metasoma yellowish-red.
In this sense, Symmes allows Symzonians as animal food only oysters and similar "testaceous creatures": these have "so little visible animation" that they are considered by Symzonians to be on a par with vegetables (Symmes 2009: 106).
The Mineral Conchology of Great Britain; or Coloured Figures and Descriptions of Those Remains of Testaceous Animals or Shells Which Have Been Preserved at Various Times and Depths in the Earth, 1, 1-19.
Report on the marine testaceous Mollusca of the north-east Atlantic and neighbouring seas.
Big and large; all body covered with yellow or ash colored on the testaceous or reddish ground, with black prothorax and head.
Thorax: Mesonotum red chestnut, with white tomentum and defined longitudinal testaceous bands; pleura and humeral callus orange with fine white tomentum; anterior and posterior spiracles pale yellow; legs with coxae, trochantes and femora orange, mid and posterior femora with apexes dark chestnut; mid femur with three apical posterodorsal setae and one antero-medial setae.
COLORATION: Dorsum coloration variable, from reddish brown with pale markings to pale brown with reddish markings; head either testaceous or reddish brown, with median longitudinal sulcus darker; AI orange, red or yellow, AII, AIII, and AIV usually yellow, with bases and apices redor orange.
But our deluded people attributed the victory not only to their fetishes, but also to every cartilaginous, spinous, and testaceous creature in the sea, which they consider, to the present day, as warriors of their fetish Nai (the sea).