Criminal Defense Glossary

Definitions of legal concepts, evidence terminology, and procedural terms used in criminal defense, written for defendants, not lawyers.

Brady Material: Evidence the prosecution possesses that is favorable to the defendant. Under Brady v. Maryland (1963), prosecutors must disclose this evidence. Failure to do so is a Brady violation, grounds for appeal or dismissal.
Chain of Custody: The documented trail of evidence from the scene to the courtroom. Gaps in the chain, missing logs, unsigned transfers, weight discrepancies, can render evidence inadmissible.
Constructive Possession: A legal theory allowing charges for possession of items not physically on the defendant. Prosecutors must prove knowledge and control, proximity alone is not sufficient.
Discovery: The process by which the prosecution shares evidence with the defense, police reports, lab results, witness statements, surveillance footage. Defendants have a right to this material.
Field Sobriety Test: A series of physical and cognitive tests administered roadside during a DUI stop. These tests have documented error rates, the one-leg stand has a 35% false-positive rate even when administered correctly.
Plea Bargain: An agreement between the defendant and prosecutor where the defendant pleads guilty to a lesser charge in exchange for a reduced sentence. Over 90% of criminal cases are resolved this way.
Sentencing Guidelines: Federal or state frameworks that recommend sentence ranges based on offense severity and criminal history. Judges may depart from guidelines with documented reasons.
Suppression Motion: A motion to exclude evidence obtained in violation of constitutional rights (4th Amendment search, Miranda violations). Must typically be filed within 30 days of arraignment.

Important: This glossary provides general legal information for criminal defendants. It is not legal advice. Decisions about how any term applies to your case stay with you and your attorney.