Wordnet 3.0
NOUN (1)
1. 
 beneath the B-horizon and above the bedrock; 
 consisting of weathered rock; 
[syn: C-horizon, C horizon]
WordNet (r) 3.0 (2006):
C horizon
    n 1: beneath the B-horizon and above the bedrock; consisting of
         weathered rock [syn: C-horizon, C horizon]