The Collaborative International Dictionary of English v.0.48:

Humus \Hu"mus\, n. [L., the earth, ground, soil.]
   That portion of the soil formed by the decomposition of
   animal or vegetable matter. It is a valuable constituent of
   soils. --Graham.
   [1913 Webster]

WordNet (r) 3.0 (2006):

humus
    n 1: partially decomposed organic matter; the organic component
         of soil
    2: a thick spread made from mashed chickpeas, tahini, lemon
       juice and garlic; used especially as a dip for pita;
       originated in the Middle East [syn: hummus, humus,
       hommos, hoummos, humous]