n.
   - 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. 
- the true nature or essence:![]()  the pith and core of socialism. 
- vigorous and concise expression.
v.
  - remove the pith from.
- kill or immobilize (an animal) by piercing or severing the spinal cord.
Derivative
  
  Etymology
  OE pitha, of W. Gmc origin.