Sources: Oxford English Dictionary and Oxford Learner’s Dictionary.

an attack on September 11, 2001 in which two hijacked airliners were flown directly into the World Trade Center in New York City, causing the complete collapse of the twin towers, and a third airliner was flown into the Pentagon. A fourth aircraft was brought to the ground in Pennsylvania as a result of what is thought to be passenger intervention. The airliners were hijacked by Islamic fundamentalist terrorists believed to be involved with al-Qaeda. Also called September 11.
favoring or enforcing strict obedience to authority, especially that of the government, at the expense of personal freedom: the transition from an authoritarian to a democratic regime

• showing a lack of concern for the wishes or opinions of others; domineering; dictatorial: he had an authoritarian and at times belligerent manner
a minor change or addition designed to improve a text, piece of legislation, etc.: an amendment to existing bail laws

• (Amendment) an article added to the US Constitution: the First Amendment

• something which is added to soil in order to improve its texture or fertility: you can add some soil-texturizing amendments to improve soil drainage.
a draft of a proposed law presented to parliament for discussion: a debate over the civil rights bill.
having moderate political views or policies: a centrist politician.
(Congress) a national legislative body, especially that of the US. The US Congress, which meets at the Capitol in Washington, D.C., was established by the Constitution of 1787 and is composed of theSenate and the House of Representatives: changes in taxation required the approval of Congress | legislative power is held by a 72-member National Congress.

a particular session of the US Congress: the 104th Congress.
1 averse to change or innovation and holding traditional values: they were very conservative in their outlook. • (of dress or taste) sober and conventional: a conservative suit

2 (in a political context) favoring free enterprise, private ownership, and socially traditional ideas. Often contrasted with liberal (sense 1 of the adjective).
act dishonestly or unfairly in order to gain an advantage, especially in a game or examination: she always cheats at cards.
(in a legislative assembly) a procedure for ending a debate and taking a vote: over 70 of the senators voted for cloture | [as modifier] :  a cloture motion.
a system of government by the whole population or all the eligible members of a state, typically through elected representatives: capitalism and democracy are ascendant in the third world

• a state governed by a democracy: a multiparty democracy

• control of an organization or group by the majority of its members: the intended extension of industrial democracy

• the practice or principles of social equality: demands for greater democracy
the action or practice of deceiving someone by concealing or misrepresenting the truth: a web of deceit | a series of lies and deceits.
Electoral College
a body of people representing the states of the US, who formally cast votes for the election of the president and vice president.

• a body of electors chosen or appointed by a larger group.
a thing that is known or proved to be true: he ignores some historical and economic facts | a body of fact.
an authoritarian and nationalistic right-wing system of government and social organization. 

• (in general use) extreme authoritarian, oppressive, or intolerant views or practices: this is yet another example of health fascism in action

The term Fascism was first used of the totalitarian right-wing nationalist regime of Mussolini in Italy (1922–43); the regimes of the Nazis in Germany and Franco in Spain were also Fascist. Fascism tends to include a belief in the supremacy of one national or ethnic group, a contempt for democracy, an insistence on obedience to a powerful leader, and a strong demagogic approach.
an action such as a prolonged speech that obstructs progress in a legislative assembly while not technically contravening the required procedures: the bill was defeated by a Senate filibuster in June.
First Amendment
an amendment to the US Constitution that prohibits any law limiting freedom with respect to religion, expression, peaceful assembly, or the right of citizens to petition the government: the artist argued that his prints are protected by the First Amendment | [as modifier] :  the measure was intended to guarantee the First Amendment rights of unions to speak freely about political matters.
Grand Old Party (Republican Party).
House of Representatives
the lower house of the US Congress and other legislatures, including most US state governments.
free from outside control; not depending on another's authority: the study is totally independent of central government
a violent uprising against an authority or government: the insurrection was savagely put down | opposition to the new regime led to armed insurrection.
1 just behavior or treatment: a concern for justice, peace, and genuine respect for people

• the quality of being fair and reasonable: the justice of his case

• the administration of the law or authority in maintaining this: a tragic miscarriage of justice

• (Justice) the personification of justice, usually a blindfolded woman holding scales and a sword. 

2 a judge or magistrate, in particular a judge of the Supreme Court of a country or state.
lesbian, gay, bisexual, and transgender (often used to encompass any sexual orientations or gender identities that do not correspond to heterosexual norms).
lesbian, gay, bisexual, transgender, and queer (or questioning).
1 (often the law) the system of rules which a particular country or community recognizes as regulating the actions of its members and which it may enforce by the imposition of penalties: they were taken to court for breaking the law | [as modifier] :  law enforcement | a license is required by law

• an individual rule as part of a system of law: an initiative to tighten up the laws on pornography

• systems of law as a subject of study or as the basis of the legal profession: he was still practicing law | [as modifier] :  a law firm. Compare with jurisprudence.

• statutory law and the common law. Compare with equity.

• a thing regarded as having the binding force or effect of a formal system of rules: what he said was law

• (the law) informal the police: he'd never been in trouble with the law in his life.
relating to a person or group favoring liberal, socialist, or radical views: left politics.
an intentionally false statement: the whole thing is a pack of lies | Mungo felt a pang of shame at telling Alice a lie

• used with reference to a situation involving deception or founded on a mistaken impression: all their married life she had been living a lie.
a person who holds moderate views, especially in politics: an unlikely alliance of radicals and moderates.
identification with one's own nation and support for its interests, especially to the exclusion or detriment of the interests of other nations: their nationalism is tempered by a desire to join the European Union

• advocacy of or support for the political independence of a particular nation or people: Scottish nationalism.
(of a group, person, or idea) favoring or implementing social reform or new, liberal ideas: a relatively progressive governor

favoring or promoting change or innovation: a progressive art school.
a strong supporter of a party, cause, or person: partisans of the exiled Stuarts.
the elected head of a republican state: the Irish president | [as title] : President Kennedy.
Political Action Committee (PAC)
an organization that raises money privately to influence elections or legislation, especially at the federal level: her political action committee has raised almost $900,000 this election cycle.
a person who advocates thorough or complete political or social reform; a member of a political party or part of a party pursuing such aims.
1 the world or the state of things as they actually exist, as opposed toan idealistic or notional idea of them: he refuses to face reality | Laura was losing touch with reality

• a thing that is actually experienced or seen, especially when this is grim or problematic: the harsh realities of life in a farming community | the law ignores the reality of the situation

• a thing that exists in fact, having previously only existed in one's mind: the paperless office may yet become a reality

• the quality of being lifelike or resembling an original: the reality of Marryat's detail. • [as modifier] relating to reality TV: a reality show

2 the state or quality of having existence or substance: youth, when death has no reality

• Philosophy existence that is absolute, self-sufficient, or objective, and not subject to human decisions or conventions.
the power of the mind to think, understand, and form judgments by a process of logic: there is a close connection between reason and emotion.
favoring conservative or reactionary views: are you politically right, left, or center?
(of a legislative or deliberative assembly) consisting of people chosen to act and speak on behalf of a wider group: the new government lacked a representative assembly

• (of a government or political system) based on elected representatives: free elections and representative democracy.
the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment: the world of science and technology

• a particular area of science: veterinary science | [count noun] :  the agricultural sciences

• a systematically organized body of knowledge on a particular subject: the science of criminology

• archaic knowledge of any kind: his rare science and his practical skill.
1. the smaller upper assembly in the US Congress, most US states, France, and other countries: the senate must ratify any treaty with a two-thirds majority. • the governing body of a university or college.

2. the state council of the ancient Roman republic and empire, which shared legislative power with the popular assemblies, administration with the magistrates, and judicial power with the knights.
Supreme Court
the highest judicial court in a country or state. 

• (in full US Supreme Court) the highest federal court in the US, consisting of nine justices and taking judicial precedence over all other courts in the nation. 
take (another person's property) without permission or legal right and without intending to return it: thieves stole her bicycle | (as adjective stolen) :  stolen goods | [no object] :  she was found guilty of stealing from her employers.
a member of a senate.
Second Amendment
an amendment (= change) to the American Constitution, part of the Bill of Rights, passed in 1791. The Second Amendment gives people the right to bear arms (= to own and carry weapons). This has become an issue because of a number of recent tragic events when one armed person has shot a number of people. There is now much disagreement over what this Amendment actually means. Some people believe it only applies to the military and others that it applies to all citizens. It states: ‘A well regulated Militia, being necessary to the security of a free State, the right of people to keep and bear Arms, shall not be infringed.’
the quality or state of being true: he had to accept the truth of her accusation

• (also the truth) that which is true or in accordance with fact or reality: tell me the truth | she found out the truth about him

• a fact or belief that is accepted as true: the emergence of scientific truths.
a person who uses unlawful violence and intimidation, especially against civilians, in the pursuit of political aims: four commercial aircraft were hijacked by terrorists | a suspected terrorist.