1. the soft, spongy tissue in the center of certain plant stems
2. the soft core of various other things, as of a bone or feather
3. the spongy, fibrous tissue lining the rind and surrounding the sections of an orange, grapefruit, etc.
4. the essential part; substance; gist
5. importancenow usually in of great pith and moment
7. to remove the pith from (a plant stem)
Webster’s New World College Dictionary, Fourth Edition, compiled by the
editors of Webster’s New World Dictionaries. Copyright © 2010 by Houghton
Mifflin Harcourt. Published by Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'pith'ME pithe < OE pitha, akin to MDu pitte, pit of a fruit, kernel, pith of a tree