A

Agents: Everyone standing for election has an agent who manages their spending, form-filling and communications with election authorities, and is usually the person scowling as the result is read out if they haven’t won.

Angry voters: Politicians are unlikely to encounter them on election night, but you might get a bit of heckling as the results are read out, especially high-profile, unpopular government ministers.

Angst: The feeling you’ve had in your stomach all day about how crucial this election result is going to be.

B

Bar charts: Notorious for appearing on leaflets to give a misleading impression of how close one party is to catching another. Always read the small print. The only bar charts that ultimately count are the results on the night.

Boat: Do you remember when the BBC spent £30,000 hiring a boat in 2010 to have an election night party with random celebrities, who got increasingly drunk and made less sense as the night wore on? So do they, and that’s why they won’t be doing it again.

Remember them? Illustration: Guardian Design

C

Change UK/the Independent Group/the Independent Group for Change: They’ve changed their name as many times as their number of candidates, but Anna Soubry, Chris Leslie and Mike Gapes are still standing under the banner of the new centrist party that so spectacularly failed to get off the ground earlier this year.

“Chaos with Ed Miliband”: A 2015 tweet from David Cameron promised: “Britain faces a simple and inescapable choice – stability and strong government with me, or chaos with Ed Miliband.” Four years later, we’ve had two general elections, one EU referendum, and three different prime ministers. ¯\_(ツ)_/¯

Constituency: The country is divided into 650 constituencies, and each is represented by an MP.

Count: After the polls close, the ballot boxes from each polling station are transferred to one central location for each constituency and counted – often overnight. By law you have to start counting within four hours of polls closing, otherwise you have to send in a report explaining why. Some of the more remote voting locations in the UK are permanently on the naughty step.

D

Deposit: To stand as an MP, you have to pay £500. You get it back if you secure more than 5% of the vote. If you don’t, bizarrely it goes to the Queen, via the Treasury. There are some candidates, like the anti-abortion campaigners who have been targeting Stella Creasy in Walthamstow, where people will cheer when they lose their deposit.

Dimbleby: No Dimbleby this election. Huw Edwards steps into the shoes of the man who presented every general election for the BBC since 1979. You can always follow @DIMBLEBOT though if you miss him.

Dogs: Expect to see a lot of pictures of dogs at polling stations in the dead hours while the polls are open. There’s really not much else to report on polling day. Bonus points if you spot a horse. You can lead it to a polling station, but you can’t make it vote etc etc.

Doorstep: Politicians will frequently reference the “doorstep” when being asked: “Doesn’t the result in Flydale North show that your leader/policy/attitude is unpopular with voters?” In reply, they will confidently assert: “That’s not what I was hearing on the doorstep, Kay.”

Illustration: Guardian Design

E



Elites: If you are an Eton-educated son of nobility, then the “elites” are the media and the civil service and remainer business leaders conspiring against the people. If you a horny-handed daughter of the soil, then it is the latte-sipping metropolitans you have in your sights. Basically, the other side.



Exit poll: At 10pm on polling day an exit poll announces the expected result. It is usually pretty accurate – hence the gasps when it emerged that in 2017’s snap election Theresa May had lost her majority.



F

False statements: It is a criminal offence to make a false statement about a candidate during the election campaign – not that anybody seems to take any notice.

First past the post: Unlike other voting systems, in the UK it is simply the candidate with the most votes in each constituency who gets to be its MP. No second choices. No transferable vote. No proportional representation. Just winner-takes-all.

G

Graphics: The bigger and more ludicrous the better, the BBC seems to think. Poor Jeremy Vine will be hopping around in front of virtual No 10s, virtual Houses of Parliament, and who knows what else. Hopefully, the cowboy accent won’t return.

H

Hot mic moment: When a politician says something, thinking that the mics have been switched off, but which gets picked up by the media. Came of age in the election sense when Gordon Brown used the phrase “bigoted woman”.

Hung parliament: When no party has won enough seats to control over half of parliament, it is described as a “hung parliament”, because it is hanging in the balance.

I

If: “If these exit poll numbers are correct, and I’m not saying they are Huw” will be the start of virtually every sentence between 10pm and 11:15pm until one of Sunderland or Newcastle is the first constituency to declare.

Independent: There might be a couple of independent candidates returned to parliament this year. Principled anti-Brexit ex-Tory rebels David Gauke and Dominic Grieve will be hoping voters will prioritise personal loyalty to their MP over party loyalty.

J

Joke candidates: There is long and proud tradition of joke candidates standing against major figures. Who can forget Lord Buckethead and Elmo opposing Theresa May in 2017? Insert your own punchline about which party leader you also think is a joke this time around.

Lord Buckethead stands alongside Theresa May in Maidenhead in the 2017 general election. Photograph: BBC News

L

Landslide: That is what the Tories are hoping for with this election – a majority in parliament of around 100+ MPs, which would allow a government to push through its programme without having to worry about rebels on their own side forcing compromise.

Lifts: Party activists will be haring round in cars trying to ferry old, vulnerable and less mobile voters to the polls to cast their votes. You’ll enjoy several people reheating on social media the old anecdote that their dad always used to get the Tories to give him a lift down to the polling station, and then voted Labour every time.

Illustration: Guardian Design

M

Manifesto: Long list of promises just waiting to be broken or contradicted.

Maps: There will be a lot of talk about the changes to the electoral map. Someone will almost certainly produce a viral tweet that compares the voting pattern in 2019 to something or other in 1919 such as coal mines or provision of public libraries. Thinking they’ve made a great point about social history, they are basically revealing that people in Britain have mostly lived in the same major urban areas for a couple of centuries. Look out for the giant election map outside the BBC’s Broadcasting House in London. It’s December, why wouldn’t you build it indoors?

Marginal seats: Parliamentary constituencies that have a history of changing hands between parties, or in which the incumbent MP has a very small majority. They are the battlegrounds on which elections can be won or lost. Eleven seats were won by fewer than 100 votes in 2017.

N

Non-voters: There are usually enough of them across the country that they could have completely overturned the result if they had showed up at the polling station.

O

“OK boomer”: Joyfully dismissive retort from millennials to the people who enjoyed free education, free healthcare, affordable housing and chunky state pensions, when they start complaining that young people these days spend too much money on avocados and that the country can’t afford any of the things Labour is promising any more.

Opinion poll: An attempt to predict the outcome of the election. It usually involves asking about 1,000 people around the country how they voted last time and how they intend to vote this time, and extrapolating a result from that. Our poll tracker shows what people have been saying – that the Tories go into the election as favourites, but that a hung parliament is still a possibility.



P

Postal vote: If you’ve already posted your vote, it might have already been opened and verified. This sometimes gives political parties a clue as to how they are performing. Don’t mention them to Laura Kuenssberg though.

Psephology: A busy night ahead expected for the Is Sir John Curtice On TV? Twitter account. Expect a lot of sightings of the legendary professor giving his view on the numbers as they come in. Psephology is the study of election results and polling numbers, and you’ll be able to follow our own Dan Sabbagh’s view on what it all means on our live blog during the night.

Purdah: A much misunderstood term. Once an election is called, civil servants and local government officials aren’t allowed to announce anything that might influence the election. There’s a 41-page guide from the Cabinet Office about what they can and can’t do. It doesn’t prevent media outlets or your Insta stories from getting political.

The Queen will have to make another speech. Illustration: Guardian Design

Q

Queen’s speech: No, not the one at Christmas that Jeremy Corbyn couldn’t remember if he watched or not, the one in parliament. And yes, we did just have one in October. But we’ll get another one before Christmas, outlining the future plans of whoever has ended up with the keys to 10 Downing Street.

Queues: “I’ve never seen queues like it at the polling station.” A regular stream of social media posts at every election since social media began.

R

Recount: If a vote is close, candidates can ask for a recount. All the ballot papers are checked and counted again until the election officials are satisfied with the result.

Returning officer: The returning officer in each area is the person charged with running the election. They are the one who gets to read out the results on national TV. It’s a bit like when they go to the jury from Syldavia in the Eurovision song contest and someone has their 15 seconds of fame.

S

Safe seat: A seat where the MP has such a large majority that it is almost impossible for them to lose.

Speaker: Traditionally, none of the major parties oppose the Commons Speaker in their constituency, so the new Speaker, Sir Lindsay Hoyle, can expect to be comfortably re-elected. He is, though, facing a challenge from an independent who has officially changed his name to Mark Brexit-Smith.

Swing: In a two-party system, the “swing” is a measure of how much support has shifted from one party to another. If party A were 4% behind party B, they’d need a swing of a fraction over 2% to catch up ie one party loses 2% support, the other party gains 2% support, and that cancels out a 4% lead. The national level of swing has become a less useful figure now that the SNP is dominating elections in Scotland and the Liberal Democrats have established their south-west strongholds.

Illustration: Guardian Design

T

Tactical voting: Casting a vote for a party you don’t particularly support, because they are more likely to win in your area against a party you definitely don’t support.

Tellers: Party activists hanging around outside polling stations asking you for your polling number, so they can cross you off their lists. In tight contests, parties may go round “knocking up” on the doors of people they think might vote for them, to try to propel them down to the polls.

Terrible night: Have a shot every time someone says: “These numbers show it has been a terrible night for [INSERT NAME OF THE OTHER PARTY]” and you’ll be drunk and asleep by quarter-past-midnight.

Turnout: The turnout figure, usually expressed as a percentage, indicates how many people out of those registered to vote did so. In the 2010s the highest was 2017, with 68.7%, the lowest was 2010, with 65.1%. It is yet to be seen how having the country’s first December election since 1923 will affect the number.

U

Undecided voters : A problem for opinion pollsters, who often exclude them from their headline figures, and the very people parties have been wooing in their campaigns. In a tight election, it is their last-minute decisions that will shape the next parliament.

#UsePens: There’s a persistent social media conspiracy theory that if you use the pencils “they” provide, “their” secret agents come along later, rub out your vote, and replace it with the vote that “they” want. If you are voting today, use pens.

V

Voter registration: There was a huge push to get voters registered and 2.8m applications were filed after the pre-Christmas election was called. If you haven’t registered to vote it is too late now. But who knows, if the result is indecisive, we might yet end up with another one in April. Sign up to vote in that one here.

W

Westminster bubble: You’ll have heard the phrase: “Politicians needed to get out of the Westminster bubble and speak to real people.” Today is the day that the “real people” get to speak. Brush up on what that is like with our Anywhere But Westminster video series.

X

X: The cross you put on your ballot paper to indicate who you want to vote for. Actually a tick, or the word “Yes” or a smiley face would probably count as well. Ballot papers will generally be accepted if there has been a clear intention to vote for one candidate. In the European parliamentary elections, a vote for the Green party was counted after the voter wrote a swear word next to all of the other candidates. Do our quiz to see how much you know about being in charge of an election, which tests you on which ballot papers you would accept.

Y

Youth vote: Every election there is a huge campaign to get young people and potential first-time voters registered and voting. In 2017, around 57% of those aged 18-19 voted, while 84% of over-70s voted. If younger people vote in large numbers today, they could significantly swing the election.

Illustration: Guardian Design

Z

Zzzzz: You struggling to stay awake in the early hours of Friday 13 December, waiting for the exit poll to turn into real results. At least you’ll have Andrew Sparrow on our politics live blog for company.