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[trey-kee-id] /ˈtreɪ ki ɪd/
noun, Botany
an elongated, tapering xylem cell having lignified, pitted, intact walls, adapted for conduction and support.
Compare vessel (def 5).
1870-75; trache(a) + -id3
Related forms
[truh-kee-i-dl, trey-kee-ahyd-l] /trəˈki ɪ dl, ˌtreɪ kiˈaɪd l/ (Show IPA),
adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for tracheid


(botany) an element of xylem tissue consisting of an elongated lignified cell with tapering ends and large pits
Derived Forms
tracheidal (trəˈkiːɪdəl; ˌtreɪkɪˈaɪdəl) adjective
Word Origin
C19: from trachea (in the sense: a vessel in a plant) + -id²
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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tracheid in Science
  (trā'kē-ĭd, -kēd')   
An elongated, water-conducting cell in xylem, one of the two kinds of tracheary elements. Tracheids have pits where the cell wall is modified into a thin membrane, across which water flows from tracheid to tracheid. The cells die when mature, leaving only their lignified cell walls. Tracheids are found in all vascular plants. Compare vessel element.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for tracheid

in botany, primitive element of xylem (fluid-conducting tissues), consisting of a single elongated cell with pointed ends and a secondary, cellulosic wall thickened with lignin (a chemical binding substance) containing numerous pits but having no perforations in the primary cell wall. At functional maturity, the cell is dead and empty; its former protoplast is represented, if at all, by a warty layer on the wall. Tracheids serve for support and for upward conduction of water and dissolved minerals in all vascular plants and are the only such elements in conifers and ferns. See also vessel.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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