The Collaborative International Dictionary of English v.0.48:

Humin \Hu"min\, n. [L. humus the earth, ground.] (Chem.)
   A bitter, brownish yellow, amorphous substance, extracted
   from vegetable mold, and also produced by the action of acids
   on certain sugars and carbohydrates; -- called also humic
   acid, ulmin, gein, ulmic or geic acid, etc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ulmin \Ul"min\, n. [L. ulmus an elm: cf. F. ulmine.] (Chem.)
   A brown amorphous substance found in decaying vegetation. Cf.
   Humin. [Formerly written ulmine.]
   [1913 Webster]