The opposite of dictatorship.
The belief is that if the majority of people want something done, then in a good democracy, the government will either recognize this, or be replaced by one that will, and it will be done.
Of course it gets a bit fuzzy from there. What if 51 percent of the population want to enslave the other 49 percent? Is that good democracy?
Many would say no, that a good democracy is also about fairness and equality. Some go further, and say that good democracy is about elimination of discrimination, affirmative action and ecological harmony.
The issue of democracy is a complex one, and until recently it was not possible to run an efficient democracy with a large population. Modern technology (eg the Internet) makes this quite feasible, but the democratic processes were designed before the conception of Internet, and hence we do not run our democracies this way.
Instead of making decisions ourselves, most democracies elect representatives who make decisions on our behalf, the representatives are divided up into senior representatives, and junior representatives, and generally we elect senior representatives who are well known, or who have served significant time as junior representatives so there is an element of trust. It has been described as the worst possible form of government except all the others which have been tried.
A good measure of democracy is this
In Australia (generally considered to be a 'good' democracy), it is a little less than 25 percent: 51 percent of people in 51 percent of the electorates (which are similar sized, except the multi-seat electorates in the Senate which are greatly dissimilar).
All one-person-one-vote-one-value democracies are semi-socialist / semi-capitalist because neither a fully socialist or a fully capitalist system is acceptable to the majority of the population. Most people believe in a mixed economy in which some things are controlled by the government (command economy), and some are based on the free market.
Unfortunately the democratic process used is actually a republic, which leaves it open to bureaucratic abuse. In short, the people end up being represented by politicians, who for just that reason are nearly the worst people to do the job.
Fundamentally, in a democracy, you get the government they deserve.