Source : Webster's Revised Unabridged Dictionary (1913)

Humic \Hu"mic\, a. [L. humus the earth, ground: cf. F. humique.]
   (Chem.)
   Pertaining to, or derived from, vegetable mold; as, humic
   acid. See {Humin}.

Source : WordNet®

humic
     adj : of or relating to or derived from humus; "humic acid"