Collins English-English Dictionary

pith [pɪθ]

1. 1. n [botany] medulla the central core of unspecialized cells surrounded by conducting tissue in stems

2. 2. n the soft fibrous tissue lining the inside of the rind in fruits such as the orange and grapefruit

3. 3. n the essential or important part, point, etc

4. 4. n weight; substance

5. 5. n the soft central part of a bone, feather, etc

6. 6. vt. [tr] to destroy the brain and spinal cord of (a laboratory animal) by piercing or severing

7. 7. vt. to kill (animals) by severing the spinal cord

8. 8. vt. to remove the pith from (a plant)

9. 9. vt. [Etymology] Old English pitha; compare Middle Low German pedik, Middle Dutch pitt(e)