First past the post, or FPTP: How we decide who's won in each constituency. All it means is that whoever gets the most votes wins – there's no fannying about with second or third preferences.
Safe seat: A constituency that's heavily tilted towards one party or another, meaning no one's really bothered about it – or about you, if you live there.
Marginal: A seat that could go either way, making it much more important.
Target seat: A marginal that's on one of the big parties' lists as being particularly important or strategic, meaning that lots of vaguely recognisable politicians will have been marching around the town centre begging voters to support their local candidate.
Swing voter: Someone who doesn't stick to one party, but drifts with the political tide. Winning their support (especially in marginals) is key to winning the election.
Floating voter: Someone who genuinely hasn't made up their mind. Like swing voters, they can expect to receive leaflets. Lots of leaflets.
Exit poll: This is taken by the BBC and others by asking a random sampling of people how they've voted as they leave the polling station. The press aren't allowed to say anything about how people have voted while polls are open, in case it influences people's vote, so the results will be revealed at 10pm after polling stations close. The various parties will spend the next two or three hours frantically attempting to spin the results away while waiting for the actual votes to be counted.
Overall majority: This means that once the votes are counted, one party ends up with more MPs than everyone else put together. There are 650 seats, but since Sinn Féin winners never take their seats (because they don't recognise the authority of the British crown) the magic figure to get a majority is 323 seats – although you could get away with a couple less, since the Speaker and his deputies, who oversee the debates, don't vote.
Hung parliament: This means that no party has a majority – which is what happened in 2010.
Coalition: When two parties formally team up to form a joint government. This is what we've had recently.
Grand coalition: This is when the two biggest parties, i.e. Labour and the Tories, form a coalition together. It's also known as a government of national unity, because it tends to only happen when things are really, really bad.
Red lines: The manifesto policies that a party insists must be part of any coalition deal, because they're so important.
Minority government: If the parties can't agree on a formal coalition, the largest party (or even the second largest) can try to form a government on its own – even though it commands a minority of the votes in the House of Commons.
Confidence and supply: A formal deal with one or more small parties to back a minority government on the absolute make-or-break votes, e.g. the Queen's Speech, the Budget, and the Autumn Statement, while opposing it on other measures. Or the larger party can try to form a government anyway and hope that it can attract enough extra support to get by (which is what Labour looks to be doing with the SNP, given that Ed Miliband has ruled out any formal deal).
The deficit: The big issue at this election is public spending. The fact is that, largely due to the financial crisis in 2008, the government has been spending more than it's collected in taxes. This is called the deficit, and it currently stands at £90.2 billion. That money will be added to the national debt, which is the total stock of everything the government owes.
Austerity: Back in 2010, the coalition – the Tories and the Lib Dems – promised to eliminate the deficit by now. Instead, they've roughly halved it, meaning that there are still more cuts to come. This process of restraining government spending is also called austerity, usually by people who don't like it very much.
Universal Credit: The welfare reform which bundles various benefits together, with the theory being that you'll never lose money by taking on more work.
Bedroom tax: The welfare reform which cracked down on benefit claimants with spare bedrooms, in an effort to discourage people using social housing that's too big for them. The government prefers to call this the "spare room subsidy", though no one else does.
Food banks: Volunteer installations, manned largely by the Trussell Trust, which feed the hungry – and, to Labour, a symbol of the inequality fostered by the coalition.
Brexit: The prospect that Britain may, after the referendum promised by the Conservatives for 2017, choose to leave the European Union.
Devolution: The transfer of power from Westminster either to local communities and councils or to the Scottish parliament at Holyrood and the Welsh Assembly in Cardiff.
The Vow: The promise made by the party leaders at Westminster before the Scottish independence referendum last year to devolve more powers to Scotland. The Smith Commission was set up to agree what these should be.
West Lothian question: Whether it is fair that a Scottish MP (for West Lothian, say) can vote on issues affecting England, such as the NHS, but an English MP can't vote on the same issues in Scotland because they're the responsibility of the Scottish parliament.
EVEL: English votes for English laws. A possible solution to the West Lothian question that would see only English MPs being able to vote on English issues. The Tories are very keen on this, because they generally have a majority in England. Labour are much less keen, because they don't.
Housing crisis: The fact that Britain is building far too few homes, causing house prices to shoot up.
Help to Buy: The government scheme that tried to address this by making it easier to buy homes, without actually doing much about the number being built.
Greenfield: Land which has remained untouched by housing development – ranging from actual fields to parks, meadows, forests etc – and so, campaigners say, shouldn't be built on.
Brownfield: Sites within towns or cities that have already been built on, so it's OK to build other stuff on them as well. The problem is that a) there's not enough of it, and b) it's more expensive, because you have to clean up the stuff that was already there, e.g. factories or rubbish dumps.
Unfunded: Technically, used to describe a promised tax cut or spending increase in the parties' manifestos that will increase the deficit because it has not been matched by restraint elsewhere. In practice, used to describe any spending commitment made by any opposition party.
Margin of error: How much your poll may be out by, based on the fact you're only talking to a few hundred people rather than the entire country. Usually around 5%.
Poll of polls: An average of all the polls taken by various companies.
Flatlining: What the poll of polls has been doing in this campaign. Basically, public opinion hasn't been changing much.
Bombshell poll: A poll whose result is significantly different from the ones immediately before it.
Rogue poll: What a bombshell poll probably actually is, because you happened to talk to a slightly unrepresentative mix of people. It's also how rival polling companies will refer to a bombshell poll unless their own results back it up.
Push poll: When you poll not to measure opinion, but to shift it through carefully phrased questions, e.g. "Does his backing for uncontrolled immigration make you more or less likely to support Ed Miliband?"
Ashcroft poll: The programme of constituency-by-constituency polling funded and carried out by Lord Ashcroft, the Tory peer, alongside the traditional national polls.
Did you want a definition of a word that isn't on the list? Message me on Twitter and I'll add it in.
Robert Colvile is UK News Director at BuzzFeed and is based in London.
Contact Robert Colvile at firstname.lastname@example.org.
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