The Constitution is the supreme law of a country that outlines the framework for governance and the rights and duties of its citizens. It defines the structure of government, the separation of powers, and the principles guiding the nation. In India, the Constitution was adopted on January 26, 1950, and is known for being the longest written constitution in the world. It ensures justice, equality, liberty, and fraternity for all citizens, serving as the backbone of the nation's democracy.