ulmin
A brown amorphous substance found in decaying vegetation.
countable, uncountable
The biological features of perennial grasses involve the decomposition of their residues during the period of domination of anaerobic processes, capable of producing active humus (ulminic acid and ulmin).
Where it comes from
Latin ulmus (โelmโ), + -in: compare French ulmine.
Adapted from the Wiktionary entry ulmin (CC BY-SA 4.0).