n.[U]

1. 【植】（木）髓
2. 骨髓；（羽毛的）毛髓
3. （橘子等皮和瓤之间的）衬皮，中果皮
4. 精髓；要旨；核心
   the pith of the matter

   事情的实质

5. 重要性，意义
6. 【古】精力，力气

vt.

1. 除去（茎）中的髓
2. 杀死；使瘫痪

n.

1. spongy white tissue lining the rind of citrus fruits.
   ▸Botany  the spongy cellular tissue in the stems and branches of many higher plants.
   ▸archaic spinal marrow.
2. the true nature or essence:
   the pith and core of socialism.
3. vigorous and concise expression.

v.

1. remove the pith from.
2. kill or immobilize (an animal) by piercing or severing the spinal cord.