The Collaborative International Dictionary of English v.0.48:

Rebellion \Re*bel"lion\ (r[-e]*b[e^]l"y[u^]n), n. [F.
   r['e]bellion, L. rebellio. See Rebel, v. i. Among the
   Romans rebellion was originally a revolt or open resistance
   to their government by nations that had been subdued in war.
   It was a renewed war.]
   1. The act of rebelling; open and avowed renunciation of the
      authority of the government to which one owes obedience,
      and resistance to its officers and laws, either by levying
      war, or by aiding others to do so; an organized uprising
      of subjects for the purpose of coercing or overthrowing
      their lawful ruler or government by force; revolt;
      insurrection.
      [1913 Webster]

            No sooner is the standard of rebellion displayed
            than men of desperate principles resort to it.
                                                  --Ames.
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   2. Open resistance to, or defiance of, lawful authority.
      [1913 Webster]

   Commission of rebellion (Eng. Law), a process of contempt
      issued on the nonappearance of a defendant, -- now
      abolished. --Wharton. --Burrill.
      [1913 Webster]

   Syn: Insurrection; sedition; revolt; mutiny; resistance;
        contumacy. See Insurrection.
        [1913 Webster]

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

COMMISSION OF REBELLION, chan. prac. The name of a writ issuing out of
chancery, generally directed to four special commissioners, named by the
plaintiff, commanding them to attach the defendant wheresoever he may be
found within the state, as a rebel and contemner of the law, so as to have
him in chancery on a certain day therein named. This writ may be issued
after an attachment with proclamation, and a return of non est inventus.
Blake's Ch. Pr. 102; Newl. Ch. Pr. 14.