All terms

Legal Terms: I

Federal & State Law Editorial TeamLast reviewed: April 2026
I-130 Petitionimmigration

A form filed by a U.S. citizen or lawful permanent resident to establish a qualifying family relationship with a foreign national seeking an immigrant visa.

I-140 Petitionimmigration

An employer-filed petition to classify a foreign worker as eligible for an employment-based immigrant visa.

I-601 Waiverimmigration

The application to waive specific grounds of inadmissibility such as fraud, certain crimes, or unlawful presence, filed concurrently with an immigrant visa or adjustment application.

A waiver of the three- or ten-year unlawful-presence bar that may be applied for and approved within the United States before departure for consular processing, reducing family separation.

The USCIS petition filed by a conditional permanent resident based on marriage to remove the conditions and obtain a 10-year green card, typically filed jointly with the spouse during the 90-day window before expiration.

ICPCfamily law

The Interstate Compact on the Placement of Children, a uniform agreement among all states ensuring that children placed across state lines for foster care or adoption receive protections and proper supervision.

IDGTtax

Acronym for intentionally defective grantor trust, a popular estate planning vehicle that allows the grantor to effectively make additional tax-free gifts by paying the trust's income tax.

Illegalitycontract law

The doctrine rendering contracts unenforceable when their formation or performance violates a statute, regulation, or public policy.

A statement that appears to be a promise but actually commits the promisor to nothing, making any resulting contract unenforceable.

Another term for demonstrative evidence, offered to help the jury understand testimony but not formally admitted as substantive proof.

Immigrant Intentimmigration

The intention to reside permanently in the United States, which most non-immigrant visa applicants must rebut through evidence of ties to a home country.

Immigrant Visaimmigration

A visa issued to a foreign national intending to live permanently in the United States, based on an approved petition by a family member or employer.

Immigration Bondimmigration

A bond posted to secure the release of a detained foreign national from immigration custody, with the amount set by an immigration judge or ICE.

A judge within the Executive Office for Immigration Review who presides over removal proceedings and decides whether a foreign national may remain in the United States.

An attorney appointed by the Attorney General who presides over removal proceedings in immigration court and issues decisions on removability and relief.

A form of relief that forgives certain grounds of inadmissibility, such as unlawful presence or fraud, allowing an otherwise ineligible foreign national to obtain a visa or green card.

Immunitygeneral

Protection from legal liability or prosecution granted by law. Types include sovereign immunity (government), diplomatic immunity, and witness immunity.

Impanelcivil procedure

To select and seat a jury for a trial.

Impeachmentconstitutional

The process of formally accusing a public official of misconduct. In evidence law, the process of attacking a witness's credibility.

Impeachment Evidencecriminal procedure

Evidence offered to attack the credibility of a witness, including prior inconsistent statements, bias, or convictions for crimes of dishonesty.

Impleadercivil procedure

The procedural device under Rule 14 by which a defendant brings a third party into the suit on a theory of derivative or secondary liability, such as indemnity or contribution.

Implied Conditioncontract law

A condition not expressly stated but inferred from the nature of the contract or the conduct of the parties.

Imputed Incomefamily law

Earnings attributed to a parent by the court when that parent is voluntarily unemployed or underemployed, based on earning capacity rather than actual income, for purposes of calculating support.

In Cameracivil procedure

Latin for 'in chambers.' A legal proceeding or review conducted privately by a judge, typically to review sensitive evidence.

A private interview of a child by the judge, typically in chambers and outside the presence of the parents, used to assess the child's preferences and well-being in custody proceedings.

In Forma Pauperiscivil procedure

Latin for 'in the manner of a pauper.' A status allowing a person who cannot afford court fees to proceed without paying them.

Latin for 'in the place of a parent.' Refers to a person or institution acting in a parental capacity.

In Remcivil procedure

A legal action directed against property rather than against a specific person.

In Terrorem Clauseestate planning

Latin for an 'in terror' provision, another name for a no-contest clause that threatens forfeiture of a bequest if the beneficiary contests the will.

Inadmissibilityimmigration

Grounds under the Immigration and Nationality Act that make a foreign national ineligible for admission to the United States, including criminal convictions, health issues, and prior immigration violations.

Inadmissibilityimmigration

Statutory grounds under INA section 212(a) that bar a noncitizen from being admitted to the United States or adjusting status, including health, criminal, security, public-charge, and prior-removal categories.

Inalienable Rightsconstitutional

Rights that cannot be surrendered, sold, or transferred to another person, such as life, liberty, and the pursuit of happiness.

The confinement of a person in a jail or prison as punishment for a crime or while awaiting trial.

Inchoatecriminal

Incomplete or not fully formed. An inchoate crime is one that has been begun but not completed, such as attempt or conspiracy.

A third party who would benefit from contract performance but whom the parties did not intend to benefit, and who therefore has no enforcement rights.

The child-support calculation method used by most states, which estimates the total amount parents would spend on the child in an intact household and apportions it between the parents based on their respective incomes.

A doctrine allowing a will to incorporate an extrinsic writing in existence at the time of execution and clearly identified, making that writing part of the will.

Incumbranceproperty

A claim or liability that is attached to property, potentially diminishing its value. Alternative spelling of encumbrance.

A contractual obligation of one party to compensate another for losses or damages. Common in business contracts and insurance policies.

A worker who provides services to another entity under terms specified in a contract, maintaining control over how the work is performed and not classified as an employee.

Independent Source Doctrinecriminal procedure

An exception permitting admission of evidence initially discovered through illegal means if it was later obtained through a lawful, independent source.

Indeterminate Sentencingcriminal procedure

A system imposing a range of imprisonment (e.g., 5 to 10 years), with the actual release date determined by a parole board based on rehabilitation.

A federal law governing the removal and placement of Native American children in foster or adoptive homes, requiring preference for placement with extended family or tribal members.

A 1968 federal law imposing most of the protections of the Bill of Rights on tribal governments in their dealings with individuals.

The provision of the U.S. Constitution granting Congress the power to regulate commerce with Indian tribes, forming a basis for federal Indian law.

A legal term defined by federal statute encompassing all land within the limits of any Indian reservation, dependent Indian communities, and Indian allotments.

A federal law establishing the framework for the operation and regulation of gaming on Indian lands, requiring tribal-state compacts for Class III gaming.

A 1934 federal law reversing the allotment policy, encouraging tribal self-governance, and providing for the establishment of tribal constitutions and corporate charters.

Indictmentcriminal

A formal written accusation issued by a grand jury charging a person with a crime, based on a finding of probable cause.

Indictmentcriminal procedure

A formal written accusation by a grand jury charging a person with a serious crime, required by the Fifth Amendment for federal felonies.

Induced Infringementintellectual property

Liability for actively encouraging or inducing infringement by others, recognized in copyright (MGM v. Grokster) and patent law (35 U.S.C. Section 271(b)).

A Sixth Amendment claim that defense counsel's performance was deficient and prejudiced the outcome, evaluated under the Strickland test.

Inevitable Discoverycriminal procedure

An exception allowing admission of illegally obtained evidence if the prosecution proves it would inevitably have been discovered through lawful means.

Infractioncriminal

A minor violation of a law or rule, less serious than a misdemeanor, typically punishable only by a fine.

Infringementintellectual property

The unauthorized use of a protected intellectual property right, such as a patent, copyright, or trademark.

Infringementintellectual property

The unauthorized making, using, offering to sell, selling, or importing of a claimed invention during the patent term, actionable under 35 U.S.C. Section 271.

The process of comparing an accused product or process to the claims of a patent to determine whether the patent's rights have been violated.

A legal assertion by an IP owner that another party has violated their exclusive rights under patent, copyright, or trademark law.

Property or assets received from a deceased person through a will or intestate succession.

The first sale of a company's stock to the public, transitioning the company from private to public ownership.

Injunctioncivil procedure

A court order requiring a party to do or refrain from doing a specific act. Types include temporary restraining orders, preliminary injunctions, and permanent injunctions.

Injunctioncontract law

An equitable order requiring a party to do or refrain from doing a specific act, available in contract cases to enforce negative covenants such as non-competes.

A court order directing the infringer to stop making, using, or selling the patented invention, granted based on a four-factor equitable test.

A false assertion made honestly and without negligence, which may still permit rescission though not damages under modern contract doctrine.

A provision allowing a spouse to be relieved of joint tax liability when the other spouse improperly reported or omitted income on a joint return without the innocent spouse's knowledge.

Innocent-Owner Defensecriminal procedure

A statutory defense to civil forfeiture for owners who did not know of, or took reasonable steps to prevent, the property's illegal use.

Insane Delusionestate planning

A persistent false belief, unsupported by evidence, that materially affects the dispositions in a will, invalidating those provisions to which the delusion relates.

Insanity Defensecriminal procedure

An affirmative defense asserting that the defendant lacked criminal responsibility due to a severe mental disease or defect, with standards varying by jurisdiction.

Inside Basisbusiness

The partnership's basis in its assets, which generally equals the partners' aggregate outside basis at formation and is adjusted for partnership-level activity.

Insider Tradingsecurities

The buying or selling of a publicly traded security by someone who possesses material nonpublic information about that security.

Insolvencybankruptcy

The condition of being unable to pay debts as they become due. A prerequisite for many bankruptcy filings.

Insolvencybankruptcy

A financial condition where a person's or entity's liabilities exceed the fair market value of their assets, or where they are unable to pay debts as they come due.

An arrangement with the IRS allowing a taxpayer to pay their tax liability over time through regular monthly payments.

Integrationestate planning

The doctrine identifying which physical pages comprise the will, requiring that all sheets be present at execution and intended by the testator to be part of the document.

Integration Clausecontract law

A contractual provision declaring the writing to be the complete and final expression of the parties' agreement, strengthening parol evidence exclusion.

Intellectual Propertyintellectual property

Legal rights protecting creations of the mind, including patents, copyrights, trademarks, and trade secrets.

A third party whom the contracting parties intended to benefit and who acquires enforceable rights under the contract.

Intentcriminal

The state of mind accompanying an act. In criminal law, intent (mens rea) is a key element in determining culpability.

Intent-to-Use Applicationintellectual property

A trademark application filed under Section 1(b) of the Lanham Act based on a bona fide intent to use the mark in commerce, requiring later filing of a statement of use to mature into registration.

A trust deliberately drafted to be a grantor trust for income tax purposes (so grantor pays the tax) while being completed for transfer tax purposes, enabling tax-efficient wealth transfer.

A post-grant proceeding before the Patent Trial and Appeal Board to challenge the validity of a patent based on prior art consisting of patents or printed publications.

Inter Partes Reviewintellectual property

A USPTO administrative trial proceeding before the PTAB allowing a third party to challenge the validity of issued patent claims based on prior art patents and printed publications.

Interlocutorycivil procedure

A temporary or provisional court order that is not a final judgment, such as a preliminary injunction.

Interlocutory Appealcivil procedure

An appeal from a non-final order, permitted only in limited circumstances such as 28 USC 1292(a)(1) injunctions or by certification under 1292(b).

Interrogatoriescivil procedure

Written questions under Rule 33 served on another party, who must answer or object under oath within 30 days, limited to 25 questions without leave of court.

Interrogatorycivil procedure

A set of written questions sent by one party to another during the discovery phase of litigation, which must be answered under oath.

Interstate Commerceconstitutional

Commercial activity that crosses state borders, which Congress has the power to regulate under the Commerce Clause of the Constitution.

Interventioncivil procedure

The procedure under Rule 24 by which a non-party joins ongoing litigation, either as of right when it has a protectable interest or permissively at the court's discretion.

Intestateestate

Dying without a valid will. The deceased person's property is distributed according to state intestacy laws.

Intestateestate planning

Dying without a valid will, causing the decedent's probate estate to pass to heirs according to the state's intestate succession statute.

Intestate Successionestate planning

The statutory scheme that distributes the property of a person who dies without a valid will, typically prioritizing surviving spouse, descendants, parents, and more distant relatives in defined shares.

The unintentional killing of a person through criminal negligence or during the commission of a non-felony crime.

A bankruptcy case filed against a debtor by creditors, forcing the debtor into bankruptcy if the creditors can show the debtor is generally not paying debts as they come due.

Involuntary TPRfamily law

A court-ordered termination of parental rights over the parent's objection, based on statutory grounds such as abandonment, chronic abuse, or failure to remedy conditions leading to removal.

IPR Petitionintellectual property

A petition filed by a third party initiating an inter partes review proceeding before the PTAB, subject to a one-year time bar from service of an infringement complaint on the petitioner.

Iqbal Plausibilitycivil procedure

The extension in Ashcroft v. Iqbal (2009) of the Twombly plausibility standard to all civil cases, requiring courts to disregard conclusory allegations.

A presumption that conclusively establishes a fact and cannot be overcome by evidence, functioning effectively as a rule of substantive law.

A no-fault ground for divorce premised on the parties' inability to resolve fundamental conflicts, supporting dissolution without proof of misconduct.

Irresistible Impulse Testcriminal procedure

An insanity standard adding a volitional component to M'Naghten, asking whether the defendant could control their conduct even if they knew it was wrong.

A no-fault ground for divorce indicating that the marriage cannot be repaired, typically requiring a sworn statement and sometimes a waiting period before the decree may issue.

A type of stock option that, if statutory requirements are satisfied, receives favorable tax treatment under IRC Section 422, with no ordinary income on exercise (subject to AMT) and capital gain on qualifying dispositions.

Specific expenses that individual taxpayers can deduct from adjusted gross income instead of taking the standard deduction, including mortgage interest, state taxes, and charitable contributions.

Deductions claimed on Schedule A in lieu of the standard deduction, including state and local taxes (subject to SALT cap), mortgage interest, charitable contributions, and certain medical expenses.

This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.