Search Result for "endotoxin": 
Wordnet 3.0

NOUN (1)

1. a toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die; 



WordNet (r) 3.0 (2006):

endotoxin
    n 1: a toxin that is confined inside the microorganisms and is
         released only when the microorganisms are broken down or
         die [ant: exotoxin]