The Collaborative International Dictionary of English v.0.48:

Afforce \Af*force"\, v. t. [OF. afforcier, LL. affortiare; ad +
   fortiare, fr. L. fortis strong.]
   To re["e]nforce; to strengthen. --Hallam.
   [1913 Webster]

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

AFFORCE, AFFORCEMENT OF THE ASSIZE, Old English law, practice. An ancient
practice in trials by jury, which is explained by Bracton, (fo. 185, b. 292
a) and by the author of Fleta, lib. 4, cap. 9, Sec. 2. It consisted in
adding other jurors to the panel of jurors, after the cause had been
committed to them, in case they could not agree in a verdict. The author of
Fleta (ubi sup) thus describes it. The oath having been administered to the
jury, the (prenotarius) prothonotary, addressed them thus: "You will say
upon the oath you have taken, whether such a one unjustly and without
judgment disseised such a one of his freehold in such a ville within three
years or not." The justices also repeat for the instruction of, the jurors
the plaint of the plaintiff, &c. The jurors then retire and confer together,
&c. If the jurors differ among themselves and cannot agree in one
(sententiam) finding, it will be in the discretion of the judges, &c; to
afforce the assize by others, provided there remain of the jurors summoned
many as the major party of the dissenting jurors; or they may compel the
same jurors to unanimity, viz. by directing the sheriff to keep them safely
without, meat or drink until they agree. The object of adding to the panel a
number equal to the major party of the dissenting jurors, was to ensure a
verdict by twelve of them, if the jurors thus added to the panel should
concur with the minor party of the dissenting jurors. This practice of
afforcing the assize, was in reality a second trial of the cause, and was
abandoned, because the courts found it would save delay and trouble by
insisting upon unanimity. The practice of confining jurors without meat and
drink in order to enforce unanimity, has in more modern times also been
abandoned and the more rational practice adopted of discharging the jury and
summoning a new one for the trial of the cause, in cases where they cannot
agree. This expedient for enforcing unanimity was probably introduced from
the canon law, as we find it was resorted to on the continent, in other
cases where the unanimity of a consultative or deliberative body was deemed
indispensable. See Barring. on Stats. 19, 20; 1, Fournel, Hist. des Avocats,
28, note.

  TO AFFRANCHISE. To make free.

  AFFRAY, criminal law. The fighting of two or more persons, in some public
place, to the terror of the people.
     2. To constitute this offence there must be, 1st, a fighting; 2d, the
fighting must be between two or more persons; 3d, it must be in some public
place ; 4th, it must be to the terror of the people.
     3. It differs from a riot, it not being premeditated; for if any
persons meet together upon any lawful or innocent occasion, and happen on a
sudden to engage in fighting, they are not guilty of a riot but an affray
only; and in that case none are guilty except those actually engaged in it.
Hawk. b. 1, c. 65, s. 3 ; 4 Bl. Com. 146; 1 Russell, 271.