Absentee ballott
A vote cast by someone who cannot reach a polling station. Can be postal or by proxy.
By-election
An election held between general elections, usually because the sitting MP has died or resigned.
Cabinet
The group of senior ministers at the head of the government.
Candidate
Someone putting themselves up for election. Once Parliament has been dissolved, there are no MPs, only candidates.
Canvassing
During a campaign, active supporters of a party ask voters who they will vote for and try to drum up support for their own candidates.
Electoral register
A list of all those in a constituency entitled to vote. Also known as electoral roll.
General election
Election at which all seats in the House of Commons are contested.
Majority government
When one party wins more than half of the seats in the Commons, they can rule alone in a majority government.
Manifesto
A public declaration of a party's ideas and policies, usually printed during the campaign. Once in power, a government is often judged by how many of its manifesto promises it manages to deliver.
MP (Member of Parliament)
Strictly this includes members of the House of Lords, but in practice means only members of the House of Commons. When an election is called Parliament is dissolved and there are no more MPs until it assembles again.
Opinion poll
A survey asking people's opinion on one or more issues. In an election campaign, the key question is usually about which party people will vote for.
Opposition
The largest party not in government is known as the official opposition. It receives extra parliamentary funding in recognition of its status.
Poll
Another term for vote or election.
Polling station
Place where people go to cast their votes.
Postal vote
People unable to get to a polling station are allowed to vote by post if they apply in advance.
Prorogation
The act of ending a session of Parliament. Performed when an election is called.
Proxy vote
People unable to get to a polling station are allowed to appoint someone to vote on their behalf if they apply in advance. They are also allowed a postal vote.
Speaker
An MP elected by other members of the Commons to chair debates and deal with the running of the Commons. By tradition, an MP who is Speaker is not opposed by any of the main parties at elections.
Tactical voting
This is when people vote not for the party they really support, but for another party in order to keep out a more disliked rival.
Turnout
The number or percentage of people eligible to vote in a constituency who actually "turn out" to the polling station to do so (or send in their postal vote).
All information on this page is from BBC (2015)