Search Result for "supercritical": 
Wordnet 3.0

ADJECTIVE (1)

1. (especially of fissionable material) able to sustain a chain reaction in such a manner that the rate of reaction increases; 



WordNet (r) 3.0 (2006):

supercritical
    adj 1: (especially of fissionable material) able to sustain a
           chain reaction in such a manner that the rate of reaction
           increases