Lighting is a lamp which you can turn on if it gets dark. Then you can see the light. Enlightenment stands for thinking for yourself. Being clear in your ideas and not just copying what others say.
The political and philosophical movement behind this idea started in 1650 and lasted until about the time of the French Revolution (end of the 18th century). The adherents of the Enlightenment initiated, among other things, religious freedom and freedom of ideas. The movement revolutionised thinking in the Western world.