The terms left and right in politics originated during the French Revolution in 1789.
In the French National Assembly, delegates physically sat in different parts of the chamber according to their political views. The seating arrangement became a convenient shorthand for political beliefs and the labels eventually spread throughout Europe and the wider world.
The left-right distinction still captures something important – particularly attitudes toward economics, taxation, welfare, and the role of government – but it struggles to explain many of today’s political divisions.