Old English piþa, from Proto-Germanic *piþan (compare West Frisian piid 'pulp, kernel', Dutch peen 'carrot', Low German Peddik 'pulp, core'), from earlier *piþō (oblique *pittan). Doublet of pit. The verb meaning "to kill by cutting or piercing the spinal cord" is attested 1805.
- The soft spongy substance in the center of the stems of many plants and trees.
- The spongy interior substance of a feather.
- The spinal cord; the marrow.
- (figuratively) The essential or vital part.
- The pith of my idea is truth.
- enterprises of great pith and moment
- (essential or necessary part): core, essence, general tenor, gist, heart, heart and soul, inwardness, kernel, marrow, meat, nitty-gritty, nub, quintessence, soul, spirit, stuff, substance