A geographic area, covering two or more countries, which share the same custom regulations. Under Boris Johnson's Brexit deal, Northern Ireland and Great Britain will remain part of the same customs territory - although Northern Ireland will need to continue to follow EU custom rules.
The EU customs union is an agreement between EU countries not to charge taxes called tariffs on things coming from other EU countries, and to charge the same tariffs as each other on things coming from outside the EU. Jersey will enter into a customs union with the UK at the end of the Transition Period.
Free Trade Agreement (FTA)
A deal between countries to reduce, but not necessarily eliminate, trade barriers. These barriers include import or export taxes (tariffs), quotas or licences that limit imports, and differing regulations on things such as safety or hygiene or labelling. The aim is increase trade in goods but also services.
One of the four freedoms associated with the single market is free movement of people. This lets EU citizens travel, live, study and work in any member country. There can be no discrimination in access to public services and benefits.
Trying to do business between the UK and the European Union with the minimum of tariffs, quotas, customs checks and other obstructions.
Level playing field
A set of rules that EU countries need to follow when it comes to areas such as: workers' rights, state aid and competition policy. The rules are meant to ensure that no EU country has an unfair advantage over another. However, Mr Johnson wants to have the option to diverge from all these rules in the future. Free trade agreements between non-EU countries also contain level playing field provisions.
A no-deal Brexit would mean the UK leaving the European Union and cutting ties immediately, with no agreement in place. However, the UK left on 31 January with the withdrawal deal negotiated by Boris Johnson. A transition period started on the next day, ending on December 31 2020. If no UK-EU trade deal is ready, the UK would then have to follow World Trade Organization rules to trade with the EU and other countries, until a deal is ready to be implemented.
No further negotiated outcome
There is the possibility that no future relationship, or even a basic trading agreement, will be reached and both the UK and EU would then default to trading on simpler, less favourable WTO terms. This outcome is known as a No Further Negotiated Outcome (NFNO).
EU citizens and their families who have been living in the UK for five years can apply for "settled status", which allows them to stay in the UK for as long as they wish. Any child born in the UK to a mother with settled status will automatically become a British citizen. Settled status means you can work in the UK, use the NHS, have access to pensions and benefits and travel in and out of the UK. Applications from people with serious criminal convictions, or where there are other security concerns, can be rejected. Jersey operates an almost identical scheme, the Jersey-EU Settlement Scheme, to allow the significant number of EU nationals living in the Island to obtain a residential status.
Jersey Settled Status scheme
A system that enables goods, services, people and capital (money) to move between all 27 EU member states, as well as Iceland, Norway, Liechtenstein and Switzerland. Countries in the single market apply many common rules and standards. A UK company has been able to sell its product (goods) in Portugal as easily as it can in Portsmouth, bring back the cash (capital), offer maintenance (services) and despatch a repair team (people).
A tax or duty to be paid on goods being imported or, very occasionally, exported.
Trade without any taxes or duties to pay when goods are imported or exported.
The transition period is intended to allow time for the UK and EU to agree their future relationship. The UK will have no say in the making of new EU laws during the transition but will have to follow all EU rules, including freedom of movement. The transition is due to last until 31 December 2020 and could be extended by up to two years if both the UK and the EU wanted. However, the Prime Minister has ruled out any extension to the transition.
Theresa May agreed a deal with the EU on the terms of the UK's departure. It included how much money the UK must pay to the EU as a settlement, details of the transition period, and citizens' rights. It also covered the so-called "backstop", which ensures that no hard border exists between Northern Ireland and the Republic of Ireland after Brexit even if there's no deal on the future relationship in place by the end of the transition period. After it was voted down three times and Mrs May resigned, Boris Johnson negotiated changes to the withdrawal agreement where the backstop was replaced with a new Northern Ireland proposal.
If countries don't have free-trade agreements, they usually trade with each other under rules set by the World Trade Organization. Each country sets tariffs, or taxes, on goods entering. For example, cars passing from non-EU countries to the EU are charged at 10% of their value. But tariffs on some agricultural products are much higher (dairy averages more than 35%). If the UK chooses to put no tariffs on goods from the EU, it must also have no tariffs on goods from every WTO member.