In the dictionary definition, democracy is government by the people in which the supreme power is vested in the people and exercised directly by them or by their elected agents under a free electoral system.
In the words of Abraham Lincoln, democracy is a government “of the people, by the people, and for the people.
Following are the varied definition of democracy.
“Democracy comes from the Greek words demos meaning ‘People’ and kratos meaning ‘authority’ or ‘power. Government which is conducted with the freely given consent of people a system of government in which supreme authority lies with the people.”
Rule by the people in a country directly or by representation.
“The form of government in which political control exercised by all the people, either directly or through their elected representative.”
The word ‘democracy’ itself means ‘rule by the people. “A democracy is a system where people can change their rulers in a peaceful manner and the government is given the right to rule because the people say it may.
Direct democracy: 
In a direct democracy, all citizens, without the intermediary of elected or appointed officials, can participate in making public decisions. Such a system is clearly only practical with relatively small numbers of people in a community organization to tribal council, for example, or the local unit of a labor union, where members can meet in a single room to discuss issues and arrive at decisions by consensus or majority vote.
Everyone has the right to take part in the government of his country, directly or though freely chosen representatives. The will of the people shall be the basis of the authority of government; this shall be expressed in periodic and genuine election that shall be held by universal and equal suffrage and shall be held by secret vote or the equivalent free voting procedures.
During elections, citizens vote for the candidate for their choice. Elected leader represent “the people” and govern for a set period of office. Representatives are chosen through elections based on the constituency or proportional representation system, or on a combination of the two.
Constitutional democracies: 
Democracies are based on a written constitution or a supreme law that serves to guide legislators and the laws they make. Written constitutions serve as a guarantee to citizens that the government is required to act in a certain way and uphold certain rights. The strength of a real democracy depends on certain fundamental rights and freedoms. These rights and freedoms must be protected to make sure that a democracy will succeed. In many countries these rights are found in and protected by a constitution. The constitution also sets out the structures and other laws.
Merits of democracy: 
1.The participation of the individual members in the government facilitates to enlist their sympathy and co–operation to the success of the government.
2.It is an effective form to educate the public about political, economic and social affairs.
3.It is helpful to promote patriotism among the people and prevents occurrence of violent revolutions.
4.It helps to make progress and development and enables changes to take place in a peaceful manner.
5.It ensures to the people freedom of speech, conscience, assembly and action.
6. It guarantees liberty and equality, which are necessary for human development.
Demerits of democracy: 
1. It sometimes leads to establish the majority view over the minority view.
2.Party leaders and political office holders in government control the citizens and the members of the party.
3.It does not encourage individuals to give their opinions.
4. It is a very expensive form of government because elections have to be conducted periodically to various offices.
5.It is difficult to prevent corruption and malpractices.
6.It is also known as government by amateurs and lead to domination of masses.