The Collaborative International Dictionary of English v.0.48:

Perjury \Per"ju*ry\, n.; pl. Perjuries. [L. perjurium. See
   Perjure, v.]
   1. False swearing.
      [1913 Webster]

   2. (Law) At common law, a willfully false statement in a fact
      material to the issue, made by a witness under oath in a
      competent judicial proceeding. By statute the penalties of
      perjury are imposed on the making of willfully false
      affirmations.
      [1913 Webster]

   Note: If a man swear falsely in nonjudicial affidavits, it is
         made perjury by statute in some jurisdictions in the
         United States.
         [1913 Webster]

WordNet (r) 3.0 (2006):

perjury
    n 1: criminal offense of making false statements under oath
         [syn: perjury, bearing false witness, lying under
         oath]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "perjury":
   artfulness, coloring, confabulation, craftiness, credibility gap,
   deceitfulness, disingenuousness, distortion, equivocation,
   exaggeration, false coloring, false swearing, falseheartedness,
   falsification, falsifying, forswearing, fraud, insincerity,
   intrigue, lying, mendaciousness, mendacity, miscoloring,
   misconstruction, misrepresentation, misstatement, perversion,
   prevarication, sharp practice, straining, uncandidness, uncandor,
   unfrankness, unsincereness, untruthfulness



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

PERJURY, crim. law. This offence at common law is defined to be a willful
false oath, by one who being lawfully required to depose the truth in any
judicial proceedings, swears absolutely in a matter material to the point in
question, whether he be believed or not.
     2. If we analyze this definition we will find, 1st. That the oath must
be willful. 2d. That it must be false. 3d. That the party was lawfully
sworn. 4th. That the proceeding was judicial. 6th. That the assertion was
absolute. 6th. That the falsehood was material to the point in question.
     3.-1. The intention must be willful. The oath must be taken and the
falsehood asserted with deliberation, and a consciousness of the nature of
the statement made; for if it has arisen in consequence of inadvertency,
surprise or mistake of the import of the question, there was no corrupt
motive; Hawk. B. 1, c. 69, s. 2; but one who swears willfully and
deliberately to a matter which he rashly believes, which is false, and which
he had no probable cause for believing, is guilty of perjury. 6 Binn. R.
249. See 1 Baldw. 370; 1 Bailey, 50.
     4.-2. The oath must be false. The party must believe that what he is
swearing is fictitious; for, if intending to deceive, he asserts that which
may happen to be true, without any knowledge of the fact, he is equally
criminal, and the accidental truth of his evidence will not excuse him. 3
Inst. 166 Hawk. B. 1, c. 69, s. 6.
     5.-3. The party must be lawfully sworn. The person by whom the oath
is administered must have competent authority to receive it; an oath,
therefore, taken before a private person, or before an officer having no
jurisdiction, will not amount to perjury. 3 Inst. 166; 1 Johns. R. 498; 9
Cowen, R. 30; 3 McCord, R. 308; 4 McCord, It. 165; 2 Russ. on Cr. 520; 3
Carr. & Payne, 419; S. C. 14 Eng. Com. Law Rep. 376; 2 Chitt. Cr. Law, 304;
4 Hawks, 182; 1 N. & M. 546; 3 McCord, 308; 2 Hayw. 56; 8 Pick. 453.
     6.-4. The proceedings must be judicial. Proceedings before those who
are in any way entrusted with the administration of justice, in respect of
any matter regularly before them, are considered as judicial for this
purpose. 2 Chitt. Crim. C. 303; 2 Russ. on Cr. 518; Hawk. B. 1, c. 69, s. 3.
Vide 3 Yeates, R. 414; 9 Pet. Rep. 238. Perjury cannot therefore be
committed in a case of which the court had no jurisdiction. 4 Hawks, 182; 2
Hayw. 56; 3 McCord, 308; 8 Pick. 453: 1 N. & McC. 546.
     7.-5. The assertion must be absolute. If a man, however, swears that
he believes that to be true which he knows to be false, it will be perjury.
2 Russ. on Cr. 518; 3 Wils. 427; 2 Bl. Rep. 881; 1 Leach, 242; 6 Binn. Rep.
249; Lofft's Gilb. Ev. 662.
     8.-6. The oath must be material to the question depending. Where the
facts sworn to are wholly foreign from the purpose and altogether immaterial
to the matter in question, the oath does not amount to a legal perjury. 2
Russell on Cr. 521; 3 Inst. 167; 8 Ves. jun. 35; 2 Rolle, 41, 42, 369; 1
Hawk. B. 1, c. 69, s. 8; Bac. Ab. Perjury, A; 2 N. & M. 118; 2 Mis. R. 158.
Nor can perjury be assigned upon the valuation under oath, of a jewel or
other thing, the value of which consists in estimation. Sid. 146; 1 Keble,
510.
     9. It is not within the plan of this work to cite all the statutes
passed by the general government, or the several states on the subject of
perjury. It is proper, however, here to transcribe a part of the 13th
section of the act of congress of March 3, 1825, which provides as follows:
"If any person in any case, matter, bearing, or other proceeding, when an
oath or affirmation shall be required to be taken or administered under or
by any law or laws of the United States, shall, upon the taking of such oath
or affirmation, knowingly and willingly swear or affirm falsely, every
person, so offending, shall be deemed guilty of perjury, and shall, on
conviction thereof, be punished by fine, not exceeding two thousand dollars,
and by imprisonment and confinement to bard labor, not exceeding five years,
according to the aggravation of the offence. And if any person or persons
shall knowingly or willingly procure any such perjury to be committed, every
person so offending shall be deemed guilty of subornation of perjury, and
shall on conviction thereof, be punished. by fine, not exceeding two
thousand dollars, and by imprisonment and confinement to bard labor, not
exceeding five years, according to the aggravation of the offence."
    10. In general it may be observed that a perjury is committed as well by
making a false affirmation, as a false oath. Vide, generally, 16 Vin. Abr.
307; Bac. Abr. h.t.; Com. Dig. Justices of the Peace, B 102 to 106; 4 Bl.
Com. 137 to 139; 3 Inst. 163 to 168; Hawk. B. 1, c. 69; Russ. on Cr. B. 5,
c. 1; 2 Chitt. Cr. L. c. 9; Roscoe on Cr. Ev. h.t.; Burn's J. h.t. Williams'
J. h.t.