The Collaborative International Dictionary of English v.0.48:

Arson \Ar"son\ ([aum]r"s'n; 277), n. [OF. arson, arsun, fr. L.
   ardere, arsum, to burn.] (Law)
   The malicious burning of a dwelling house or outhouse of
   another man, which by the common law is felony; the malicious
   and voluntary firing of a building or ship. --Wharton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

arson
    n 1: malicious burning to destroy property; "the British term
         for arson is fire-raising" [syn: arson, incendiarism,
         fire-raising]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

ARSON, criminal law. At common law an offence of the degree of felony; and
is defined by Lord Coke to be the malicious and voluntary burning of the
house of another, by night or day. 3 Inst. 66.
     2. In order to make this crime complete, there must be, 1st, a burning
of the house, or some part of it; it is sufficient if any part be consumed,
however small it may be. 9 C. & P. 45; 38 E. C. L. R. 29; 16 Mass. 105. 2d.
The house burnt must; belong to another; but if a man set fire to his own
house with a view to burn his neighbor's, and does so, it is at least a
great misdemeanor, if not a felony. 1 Hale, P. C. 568; 2 East, P. C. 1027; 2
Russ. 487. 3d. The burning must have been both malicious and willful.
     3. The offence of arson at common law, does not extend further than the
burning of the house of another. By statute this crime is greatly enlarged
in some of the states, as in Pennsylvania, where it is extended to the
burning of any barn or outhouse having bay or grain therein; any barrack,
rick or stack of hay, grain, or bark; any public buildings, church or
meeting-house, college, school or library. Act 23d April, 1829; 2 Russell on
Crimes, 486; 1 Hawk. P. C. c. 39 4 Bl. Com. 220; 2 East, P. C. c. 21, s. 1,
p. 1015; 16 John. R. 203; 16 Mass. 105. As to the extension of the offence
by the laws of the United States, see Stat. 1825, c. 276, 3 Story's L. U. S.
1999.