Definition of Forgery
The false making or the material altering of a document with the intent to defraud. A signature of a person that is made without the person’s consent and without the person otherwise authorizing it. A person is guilty of forgery if, with purpose to defraud or injure anyone, or with knowledge that he is facilitating a fraud or injury to be perpetrated by anyone, the actor: (a) alters any writing of another without his authority; or (b) makes, completes, executes, authenticates, issues or transfers any writing so that it purports to be the act of another who did not authorize that act, or to have been executed at a time or place or in a numbered sequence other than was in fact the case, or to be a copy of an original when no such original existed; or (c) utters any writing which he knows to be forged in a manner specified in paragraph (a) or (b). Model Penal Code, § 224.1. See also MPC § 241.7, "Tampering with or Fabricating Physical Evidence”.
Crime includes both act of forging handwriting of another and act of uttering as true and genuine any forged writing knowing same to be forged with intent to prejudice, damage or defraud any person. State v. May, 93 Idaho 343, 461 P.2d 126, 129. Crime is committed when one makes or passes a false instrument with intent to defraud, and the element of loss or detriment is immaterial. People v. McAffery, 182 Cal.App.2d 486, 6 Cal.Rptr. 333, 337. The false making of an instrument, which purports on face of it to be good and valid for purposes for which it was created, with a design to defraud any person or persons. State v. Goranson, 67 Wash.2d 456, 408 P.2d 7, 9.
See also Alteration; Counterfeit; False making; Falsify; Fraud; Imitation; Raised check; Utter; Uttering a forged instrument.
Evidence. The fabrication or counterfeiting of evidence. The artful and fraudulent manipulation of physical objects, or the deceitful arrangement of genuine facts or things, in such a manner as to create an erroneous impression or a false inference in the minds of those who may observe them.
That's the definition of Forgery in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.