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medullary sheath

noun
  1. Botany. a narrow zone made up of the innermost layer of woody tissue immediately surrounding the pith in plants.
  2. Anatomy. myelin sheath.

Origin of medullary sheath

First recorded in 1840–50
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for medullary sheath

medullary sheath

noun
  1. anatomy a myelin layer surrounding and insulating certain nerve fibres
  2. a layer of thick-walled cells surrounding the pith of the stems of some higher plants
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
medullary sheath in Medicine

medullary sheath

n.
  1. myelin sheath
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.