The Collaborative International Dictionary of English v.0.48:

Assize \As*size"\, n. [OE. assise, asise, OF. assise, F.
   assises, assembly of judges, the decree pronounced by them,
   tax, impost, fr. assis, assise, p. p. of asseoir, fr. L.
   assid?re to sit by; ad + sed[=e]re to sit. See Sit, Size,
   and cf. Excise, Assess.]
   1. An assembly of knights and other substantial men, with a
      bailiff or justice, in a certain place and at a certain
      time, for public business. [Obs.]
      [1913 Webster]

   2. (Law)
      (a) A special kind of jury or inquest.
      (b) A kind of writ or real action.
      (c) A verdict or finding of a jury upon such writ.
      (d) A statute or ordinance in general. Specifically: (1) A
          statute regulating the weight, measure, and
          proportions of ingredients and the price of articles
          sold in the market; as, the assize of bread and other
          provisions; (2) A statute fixing the standard of
          weights and measures.
      (e) Anything fixed or reduced to a certainty in point of
          time, number, quantity, quality, weight, measure,
          etc.; as, rent of assize. --Glanvill. --Spelman.
          --Cowell. --Blackstone. --Tomlins. --Burrill.

   Note: [This term is not now used in England in the sense of a
         writ or real action, and seldom of a jury of any kind,
         but in Scotch practice it is still technically applied
         to the jury in criminal cases. --Stephen. --Burrill.
         --Erskine.]
      (f) A court, the sitting or session of a court, for the
          trial of processes, whether civil or criminal, by a
          judge and jury. --Blackstone. --Wharton. --Encyc.
          Brit.
      (g) The periodical sessions of the judges of the superior
          courts in every county of England for the purpose of
          administering justice in the trial and determination
          of civil and criminal cases; -- usually in the plural.
          --Brande. --Wharton. --Craig. --Burrill.
      (h) The time or place of holding the court of assize; --
          generally in the plural, assizes.
          [1913 Webster]

   3. Measure; dimension; size. [In this sense now corrupted
      into size.]
      [1913 Webster]

            An hundred cubits high by just assize. --Spenser.
      [1913 Webster] [Formerly written, as in French, assise.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Assize \As*size"\, v. t. [imp. & p. p. Assized; p. pr. & vb.
   n. Assizing.] [From Assize, n.: cf. LL. assisare to
   decree in assize. Cf. Asses, v.]
   1. To assess; to value; to rate. [Obs.] --Gower.
      [1913 Webster]

   2. To fix the weight, measure, or price of, by an ordinance
      or regulation of authority. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

assize
    n 1: the regulation of weights and measures of articles offered
         for sale
    2: an ancient writ issued by a court of assize to the sheriff
       for the recovery of property

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

ASSIZE, Eng. law. This was the name of an ancient court; it derived its name
from assideo, to sit together. Litt. s. 234; Co. Litt. 153 b., 159 b. It was
a kind of jury before which no evidence was adduced, their verdict being
regarded as a statement of facts, which they knew of their own knowledge.
Bract. iv. 1, 6.
     2. The name of assize was also given to a remedy for the restitution of
a freehold, of which the complainant had been disseised. Bac. Ab. h.t.
Assizes were of four kinds: Mort d'ancestor Novel Disseisin Darrien
Presentment; and Utrum. Neale's F. & F. 84. This remedy has given way to
others less perplexed and more expeditious. Bac. Ab. h.t.; Co. Litt. 153-
155.
     3. The final judgment for the plaintiff in an assize of Novel
Disseisin, is, that he recover per visum recognitorum, and it is
sufficiently certain. if the recognitors can put the demandant in
possession. Dyer, 84 b; 10 Wentw. Pl. 221, note. In this action, the
plaintiff cannot be compelled to be nonsuited. Plowd. 11 b. See 17 Serg. &
R. 187; 1 Rawle, Rep. 48, 9.
     4. There is, however, in this class of actions, an interlocutory
judgment, or award in the nature of a judgment, and which to divers intents
and purposes, is a judgment; 11 Co. Rep. 40 b; like the judgment of quod
computet, in account render; or quod partitio fiat, in partition; quod
mensuratio fiat; ouster of aid; award of a writ of inquiry, in waste.; of
damages in trespass; upon these and the like judgments, a writ of error does
not lie. 11 Co. Rep. 40 a; Metcalf's Case, 2 Inst. 344 a: 24 Ed. III, 29 B
19.