Sentence:  The solitary, lumbering trolls of Scandinavian mythology would sometimes be turned to stone by exposure to sunlight. Barack Obama is hoping that several measures announced on June 4th will have a similarly paralysing effect on their modern incarnation, the <WSD>patent</WSD> troll. 
Meaning of the word marked with <WSD> tags:  A declaration issued by a government agency declaring someone the inventor of a new invention and having the privilege of stopping others from making, using or selling the claimed invention; a letter patent.