The Collaborative International Dictionary of English v.0.48:

cross-examination \cross"-ex*am`i*na"tion\
   (kr?s"?gz-?m`?-n?"sh?n; 115), n. (Law)
   The interrogating or questioning of a witness by the party
   against whom he has been called and examined. See
   Examination.
   [1913 Webster]

   2. [fig.] close or detailed questioning.
      [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Examination \Ex*am`i*na"tion\, n. [L. examinatio: cf. F.
   examination.]
   1. The act of examining, or state of being examined; a
      careful search, investigation, or inquiry; scrutiny by
      study or experiment.
      [1913 Webster]

   2. A process prescribed or assigned for testing
      qualification; as, the examination of a student, or of a
      candidate for admission to the bar or the ministry.
      [1913 Webster]

            He neglected the studies, . . . stood low at the
            examinations.                         --Macaulay.
      [1913 Webster]

   Examination in chief, or Direct examination (Law), that
      examination which is made of a witness by a party calling
      him.

   Cross-examination, that made by the opposite party.

   Re["e]xamination, or Re-direct examination, (Law) that
      questioning of a witness at trial made by the party
      calling the witness, after, and upon matters arising out
      of, the cross-examination; also called informally
      re-direct.

   Syn: Search; inquiry; investigation; research; scrutiny;
        inquisition; inspection; exploration.
        [1913 Webster]

WordNet (r) 3.0 (2006):

cross-examination
    n 1: (law) close questioning of a hostile witness in a court of
         law to discredit or throw a new light on the testimony
         already provided in direct examination

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

CROSS-EXAMINATION, practice. The examination of a witness, by the party who
did not call him, upon matters to which he has been examined in chief.
     2. Every party has a right to cross-examine a witness produced by his
antagonist, in order to test whether the witness has the knowledge of the
things he testifies and if, upon examination, it is found that the witness
had the means and ability to ascertain the facts about which he testifies,
then his memory, his motives, everything may be scrutinized by the cross-
examination.
    3. In cross-examinations a great latitude is allowed in the mode of
putting questions, and the counsel may put leading questions. (q.v.) Vide
further on this subject, and for some rules which limit the abuse of this
right, 1 Stark. Ev,. 96; 1 Phil. Ev. 210; 6 Watts & Serg. 75.
     4. The object of a cross-examination is to sift the evidence, and try
the credibility of a witness who has been called and given evidence in
chief. It is one of the principal tests which the law has devised for the
ascertainment of truth, and it is certainly one of the most efficacious. By
this means the situation of the witness, with respect to the parties and the
subject of litigation, his interest, his motives, his inclinations and his
prejudices, his means of obtaining a correct and certain knowledge of the
facts to which he testifies the manner in which he has used those means, his
powers of discerning the facts in the first instance, and of his capacity in
retaining and describing them, are fully investigated and ascertained. The
witness, however artful he may be, will seldom be able to elude the keen
perception of an intelligent court or jury, unless indeed his story be
founded on truth. When false, he will be liable to detection at every step.
1 Stark. Ev. 96; 1 Phil. Ev. 227; Fortese. Rep. Pref. 2 to 4; Vaugh. R. 143.
     5. In order to entitle a party to a cross-examination, the witness must
have been sworn and examined; for, even if the witness be asked a question
in chief, yet if he make no answer, the opponent has no right to cross-
examine. 1 Cr. M. & Ros. 95; 1 16 S. & R. 77; Rosc. Cr. Ev. 128; 3 Car. & P.
16; S. C. 14 E. C. L. Rep. 189; 3 Bouv. Inst. n. 3217. Formerly, however,
the rule seems to have been different. 1 Phil. Ev. 211.
     6. A cross-examination of a witness is not always necessary or
advisable. A witness tells the truth wholly or partially, or he tells a
falsehood. If he tells the whole truth, a cross-examination may have the
effect of rendering his testimony more circumstantial, and impressing the
jury with a stronger opinion of its truth. If he tells only a part of the
truth, and the part omitted is favorable to the client of the counsel cross-
examining, he should direct the attention of the witness to the matters
omitted. If the testimony of the witness be false, the whole force of the
cross-examination should be directed to his credibility. This is done by
questioning him as to his means of knowledge, his disinterestedness, and
other matters calculated to show a want of integrity or veracity, if there
is reason to believe the witness prejudiced, partial, or willfully dishonest.

Arch. Crim. Pl. 111. See Credible Witness.