Wordnet 3.0
NOUN (1)
1. 
 a small loosely aggregated mass of flocculent material suspended in or precipitated from a liquid; 
[syn: floccule, floc]
WordNet (r) 3.0 (2006):
floc
    n 1: a small loosely aggregated mass of flocculent material
         suspended in or precipitated from a liquid [syn:
         floccule, floc]