Why is a hung parliament so called?
A hung parliament is one where no political party has enough MPs to command a majority of seats (50% + 1) in the House of Commons.
A parliament is hung in the physical sense that an object suspended in air from its centre of mass hangs in equilibrium, tilting neither right nor left. In the political sense then, neither the Right nor the Left holds the balance of power.
Thus, some disagree with the use of the term "hung" and the negative connotations this carries. Some prefer to describe hung parliaments as "balanced", as neither the Right nor the Left has a monopoly on power and, theoretically, at least, they are forced to work together to strike a balance.