Search Result for "mitigating circumstance":
Wordnet 3.0

NOUN (1)

1. (law) a circumstance that does not exonerate a person but which reduces the penalty associated with the offense; 



WordNet (r) 3.0 (2006):

mitigating circumstance
    n 1: (law) a circumstance that does not exonerate a person but
         which reduces the penalty associated with the offense