A
Administrative review
You can apply for an Administrative Review if your immigration application is refused, and you do not have the right to appeal. The UKVI will review the application and make a decision.
Appeal
You have the right to appeal if your immigration application is refused. This allows you to challenge the decision in court by providing evidence in support of your case. This can include witness statements, legal arguments against the decision and expert evidence.
Appealant
This is the person appealing a decision.
B
Bail
Any person who has been detained by the Home Office in a Detention Centre for 7 days or more can apply to the first-tier tribunal for release. This is also commonly known as applying for bail.
 Barrister
A Barrister is essentially a lawyer regulated by the Bar Standards Board. They usually specialize in courtroom representation, as well as drafting pleadings and expert legal opinions.
 British Citizens
British citizens are people with citizenship in Great Britain, usually through a connection with the UK such as birth, adoption, descent, registration, or naturalization. British citizens have the right of abode in the UK.
 British Overseas Citizens
British overseas citizens are people connected with a former British Colony.
 British Overseas Territories Citizens 
British Overseas Territories Citizens are people with citizenship through a connection with a British overseas territory such as Gibraltar, St Helena.
C
Counsel
A term used to describe a barrister.
 Court of Appeal
The Court of Appeal is the highest court within the Higher Courts, including the High Court and Crown Court. If a case has been refused by the Upper Tribunal, then in some cases, it may be possible to challenge the decision by appealing to the Court of Appeal.
Curtail
If UK Immigration and Visas believe may curtail your leave,  i.e. shorten and bring it to an early end, if they believe you are no longer eligible for that leave or a decision has been made that you obtained your leave through deception. Your current leave may also be curtailed if you applied for a different kind of leave (Switching). For example, if you are in the United Kingdom as a visitor with leave to enter for 6 months and apply for asylum, your visitor leave may be curtailed.
D
Deportation
A deportation is an enforced removal of someone who is not British and has served a criminal sentence in the UK.
 Discretionary leave
If the Home Office believes that a person should be allowed to stay in the UK under exceptional circumstances, such as a medical reason, Human Rights, etc, they may grant limited leave to that individual to continue living in the UK.
Domicile
This is the country in which a person intends to settle for the rest of their life and treats as their permanent home.
E
EEA
The European Economic Area (EEA) includes all of the 28 EU member countries as well as Liechtenstein Iceland and Norway.
 Entry clearance
Entry clearance is the procedure conducted to check before a person arrives in the UK if that individual qualifies under the Immigration Rules for entry to the UK. If granted entry clearance, you will be issued with a document such as a Visa (or Entry Certificate, EEA Family Permit, or Except Vignette).  Even if you are granted entry clearance upon your application, the final decision to admit you to the UK will rest with the Immigration Officer at the Port of Entry.
 European Union
The European Union (EU) is an economic and political union that comprises of 27 countries.
Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungry, Irish Republic, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden.
F
First-tier Tribunal 
This is the first level of the Immigration Tribunal where you can appeal an asylum or immigration decision.
H
High Court
The High Court of Justice, also known as the High Court of England and Wales, deals at first instance with all high value and high importance cases and can judicially review the reasonableness and legality of decisions of lower Courts and in some cases the decisions of the Home Office.  Most immigration and asylum judicial reviews in England and Wales are now heard in the Upper Tribunal.
 Home Office
The Home Office is a Government department responsible for policies on immigration, passports, counter-terrorism, policing, drugs and crime. The Home Office is headed by the Home Secretary.
 Humanitarian Protection
Leave is granted to a person who would, if removed, face in the country of return, serious risk to life arising from the death penalty, unlawful killing or torture or inhuman or degrading treatment or punishment. If a person has been refused asylum, they may still be considered for this status. Humanitarian protection is normally granted for a period of 3 years, after which you can usually apply for indefinite leave to remain.
I
Immigration Health Surcharge (IHS)
The Immigration Health Surcharge applies to all people applying for visas to the UK for more than 6 months. It also applies to applicants already in the UK applying for limited leave to remain. The applicant is required to pay the charge to cover National Health Service (NHS) health care in the UK. The fee you pay will depend on the period of time for which you are granted leave to remain in the UK.
 Immigration Officer
Immigration officers work in passport control and are responsible for checking the right of entry to the UK of all individuals arriving at ports and via the channel tunnel. They are required to examine travel documentation and where necessary, they can use legal powers to detain or remove illegal entrants to the UK.
 Indefinite leave to remain (ILR)
Indefinite Leave to Remain is a form of settled status granted to a non-EEA national in the UK. 
There are various types of immigration applications that can lead to indefinite leave to remain eg: Family Migration Visas, Tier 1 (Investor), Tier 1 (Entrepreneur), Tier 1 (Exceptional Talent), Tier 2 (General) subject to the salary requirement, Representative of an Overseas  Business.
J
Judicial Review
A Judicial review is a procedure whereby the Courts can supervise the exercise of power, often by a public body. In immigration cases, this is usually the Home Office.  In such cases, a Judge will review the lawfulness of a decision, action or failure to act of a public body or Government department. 
A Judicial Review can also be used to challenge secondary legislation such as the Immigration Rules or policy or the compatibility of an act of parliament with rights under the European Convention on Human Rights and can only be used where all avenues of appeals have been exhausted.
L
Leave to Remain
Leave to remain is permission to stay in the UK either temporarily (limited leave to remain) or permanently (indefinite leave to remain).
 Leave to enter
This is the permission given by Immigration officials at the port of entry to enter the United Kingdom.
 Legal aid
In some instances, Legal Aid is available through Government funding to help people meet the costs of legal services they require if they are eligible to receive it.
 Licensed sponsor
This is a company or organization that is licensed by the Home Office’s UK Visas and Immigration Section to sponsor migrants to come to the United Kingdom under the points-based system (PBS).  
Limited Leave to Remain
Permission to stay in the United Kingdom temporarily, for a length of time stated on the visa.
O
Overstayer
An overstayer is a person who has been granted entry into the United Kingdom for a limited period, but who has remained longer than the time allowed on their visa without permission from the Home Office.
P
Permanent residence card
A permanent residence card is issued to non-EEA family members of EEA nationals where they have demonstrated that they have been living in accordance with the EEA Regulations for a continuous period of 5 years. The permanent residence card is valid for a period of 10 years.
 Points-Based System (PBS)
The Points-Based System is a  Home Office Immigration System used for managing applications by people who wish to come to the United Kingdom to work, train, or study. The applications are approved or refused based on how the applicant fares against the Points-Based system.
R
Removal Directions
A legal document issued by UK Visas and Immigration which states the date, time, and flight number of an enforced removal from the UK.
 Refugee

A refugee is a person who, owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of their nationality.

The individual is unable or, owing to such a fear, is unwilling to avail themselves of the protection of that country; or who not having a nationality and being outside the country of their former habitual residence, is unable or owing to such fear, is unwilling to return to it.

The Resident Labour Market Test
This is the process employers must follow to show that there is no suitable settled worker in the UK who is available to fill the job. The process involves advertising the job you want to recruit for.
Right of Abode
A legal document issued by UK Visas and Immigration states the date, time, and flight number of an enforced removal from the UK.

Right of Abode

This refers to a  person’s right to enter and live in the UK without any immigration restrictions placed upon them. All British citizens have the right of abode along with some Commonwealth citizens. This can be evidenced by a British Citizen Passport or ID card or a certificate of entitlement in a foreign passport.

S
Shortage Occupation List
Shortage occupations are ones where there are not enough settled workers to fill available jobs in particular sectors within the UK. These occupations are placed on a shortage occupation list which is published by the Home Office. The list is reviewed and amended regularly. Employers who wish to recruit a worker from outside the EEA for a vacancy on the shortage occupation list, will not need to carry out a resident labour market test.
Solicitor
A solicitor is a lawyer who has been admitted as a solicitor by the Solicitors Regulation Authority and whose name appears on the Roll of Solicitors.
Supreme Court
The highest Court in the UK. It was formerly known as the House of Lords.
Switching
Switching is a term used to describe when someone already in the United Kingdom in one immigration category, applies to extend their stay in the United Kingdom in another immigration category and without leaving the UK.
T
Temporary admission
In certain circumstances a Temporary admission can be granted by UK Visas and Immigration allowing a person to be lawfully in the UK without them being detained and without them having been granted leave to enter or remain.
U
UK Visas and Immigration (UKVI)
The UKVI is a section of the Home Office that is responsible for making decisions about who has the right to visit or stay in the UK.
UK ancestor
If you are a Commonwealth citizen, you may be able to apply to work or settle in the UK without a right of abode of you can show that you have a grandparent that was born in the UK.
V
Visa
A visa is a document issued when you apply for entry clearance which gives you permission to travel to the UK and stay here for a set period of time.
Visa application
This is an application for entry clearance which is made at a British post abroad (such as an embassy) by a person who is a national of a country requiring a visa, to travel to the UK.
Visa nationals
Nationals of certain countries will need a visa prior to traveling to the UK for any purpose, including as a visitor.