Humus (noun)

1. Decomposed organic matter in soil, formed by the breakdown of leaves, grass, and other plant material.
2. A dark organic material that is a mixture of decomposed plant material, microorganisms, and minerals, found in soil.

Origin:

Late 18th century: from latin, "earth, soil".

Examples:

1. The humus in the soil is essential for the growth of plants.
2. The addition of humus to the soil can improve its fertility.
3. Humus is a good source of nutrients for plants.
4. Humus is a rich, dark material that is an important component of healthy soil.
5. Humus is formed by the decomposition of leaves and other organic matter.