noun
pith
PITH/pɪθ/
Soft spongy tissue inside plant stems or fruit rinds.
The split stem reveals pale pith at its center.

Etymology
Old English piþa named the central substance of a plant stem and already meant an essential part figuratively. The selected sense preserves that image of an inward core.
In context
the court applied the doctrine of Pith & Substance & said that whenever you want to find out true nature of any legislation you will see the legislation as a whole
More examples
- The cut sunflower stem reveals a soft center of pith.
- Remove the bitter pith before slicing the grapefruit.
- Dried pith feels light and spongy between my fingers.
Forms
pith
Similar words
- core
- Core means a central part, not specifically its spongy tissue.