pith

v. remove the pith from plants; pierce the spinal cord of an animal

n. vital part, essence; core, central part; strength; spongy material in the center of plants; spinal cord (Archaic)

Pith is a light substance that is found in vascular plants. It consists of soft, spongy parenchyma cells, and is located in the center of the stem. It is encircled by a ring of xylem (woody tissue), and outside that, a ring of phloem (bark tissue). In most plants the pith is solid, but some plants, e.g. grasses and umbellifers, the pith has a hollow centre forming a hollow tube except at the points where leaves are produced, where there is a solid plate across the stem. A few plants, e.g. walnut, have distinctive chambered pith with numerous short cavities in the pith.
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Noun
1. soft spongelike central cylinder of the stems of most flowering plants
(hypernym) plant tissue
(substance-meronym) parenchyma
2. the choicest or most essential or most vital part of some idea or experience; "the gist of the prosecutor's argument"; "the heart and soul of the Republican Party"; "the nub of the story"
(synonym) kernel, substance, core, center, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, sum, nitty-gritty
(hypernym) content, cognitive content, mental object
(hyponym) bare bones

(v. t.)
To destroy the central nervous system of (an animal, as a frog), as by passing a stout wire or needle up and down the vertebral canal.
  

(n.)
The spongy interior substance of a feather.
  

(n.)
The spinal cord; the marrow.
  

(n.)
The soft spongy substance in the center of the stems of many plants and trees, especially those of the dicotyledonous or exogenous classes. It consists of cellular tissue.
  

(n.)
Hence: The which contains the strength of life; the vital or essential part; concentrated force; vigor; strength; importance; as, the speech lacked pith.
  

wool; pith