|1.||the soft fibrous tissue lining the inside of the rind in fruits such as the orange and grapefruit|
|2.||the essential or important part, point, etc|
|4.||botany Also called: medulla the central core of unspecialized cells surrounded by conducting tissue in stems|
|5.||the soft central part of a bone, feather, etc|
|6.||to destroy the brain and spinal cord of (a laboratory animal) by piercing or severing|
|7.||to kill (animals) by severing the spinal cord|
|8.||to remove the pith from (a plant)|
|[Old English pitha; compare Middle Low German pedik, Middle Dutch pitt(e)]|
The soft inner substance of a hair.
Spinal cord or bone marrow. No longer in technical use.
|pith (pĭth) Pronunciation Key
Noun The soft, spongy tissue in the center of the stems of most flowering plants, gymnosperms, and ferns. Pith is composed of parenchyma cells. In plants that undergo secondary growth, such as angiosperms, the pith is surrounded by the vascular tissues and is gradually compressed by the inward growth of the vascular tissue known as xylem. In plants with woody stems, the pith dries out and often disintegrates as the plant grows older, leaving the stem hollow. See illustration at xylem.