• synonyms


[proh-tuh-zahy-luh m, -lem]
noun Botany.
  1. the part of the primary xylem that develops first, consisting of narrow, thin-walled cells.
Show More

Origin of protoxylem

First recorded in 1895–1900; proto- + xylem
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for protoxylem


  1. the first-formed xylem tissue, consisting of extensible thin-walled cells thickened with rings or spirals of ligninCompare metaxylem
Show More
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

protoxylem in Science


  1. The first formed xylem that differentiates from the procambium.
Show More
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.