ar·son /'ärs-ən/ n [Anglo-French arsoun, alteration of Old French arsin, literally, conflagration, from ars, past participle of ardre to burn]: the act or crime of willfully, wrongfully, and unjustifiably setting property on fire often for the purpose of committing fraud (as on an insurance company)
ar·son·ist /-ist/ n
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.