tapetum(redirected from choroidal tapetum)
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Related to choroidal tapetum: Tapetum lucidum
n. pl. ta·pe·ta (-tə)
1. Botany A nutritive tissue that surrounds certain developing spores, particularly the microspores within an anther.
a. A reflective membrane in the back of the eye of many animals that are active during low-light conditions.
b. A layer of fibers of the corpus callosum forming the roof of part of the lateral ventricle of the brain.
[Medieval Latin tapētum, coverlet, from Latin tapēte, *tapētum, from Greek tapēs, tapēt-; see tapestry.]
ta·pe′tal (-pēt′l) adj.
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.
n, pl -ta (-tə)
1. (Botany) a layer of nutritive cells in the sporangia of ferns and anthers of flowering plants that surrounds developing spore cells
a. a membranous reflecting layer of cells in the choroid of the eye of nocturnal vertebrates
b. a similar structure in the eyes of certain nocturnal insects
3. (Anatomy) anatomy a covering layer of cells behind the retina of the eye
[C18: from New Latin, from Medieval Latin: covering, from Latin tapēte carpet, from Greek tapēs carpet]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
n., pl. -ta (-tə).
1. Bot. a layer of nutritive tissue in a developing sporangium or anther that is absorbed as the spore matures.
2. Anat. any of certain membranous layers or layered coverings, as in the choroid coat in certain animals.
[1705–15; < New Latin; Medieval Latin tapētum coverlet (Latin, only pl.) < Greek tapēt-, s. of tápēs carpet]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.