parent material

noun

: the disintegrated rock material usually unconsolidated and unchanged or only slightly changed that underlies and generally gives rise to the true soil by the natural process of soil development

called also source material

compare horizon sense 2, solum

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now