Democracy - Literally meaning in Ancient Greek 'Demos' - Peoples
The simple definition: 'Peoples Power'
My Explanation: In theory Democracy is desirable , the idea that no voice goes unheard and the power of the state is held within the people by a process of Elected representation.
An example is the UK's FPTP Electoral system where we elect MP's therefore can have influence over decision making in parliament. In the US they similarly elect senators .
People also participate through... Trade Unions , Pressure Groups , Political Party Memberships , Direct Action , Protest Movements etc.