humus
UK[ˈhjuːməs]US[ˈhjuːməs]
n
a dark, rich, organic material in soil, formed from the decay of leaves and other plant matter.
Etymology
the word 'humus' entered english in the late 18th century directly from latin, where it meant 'earth, soil, ground'. the latin term itself is a cognate of ancient greek 'khamai', meaning 'on the ground', and both derive from the proto-indo-european root dhghem-, meaning 'earth'. this root is the source of many foundational words for ground and humanity, including 'human' and 'humble'. the semantic journey is direct, from the general concept of 'earth' in its ancient source to the specific, fertile, decomposed organic component of soil in modern agronomy and soil science.
Analysis
this word is a direct loanword and is not productively segmented in modern english.
Examples
the fertility of the garden soil is largely due to its high humus content.
earthworms help to incorporate organic matter into the soil, forming humus.
compost is added to the plot to increase the level of humus and improve soil structure.