Darkness
Darkness is when there is very little light. Darkness is made by blocking light from the sun or some other source of light, which makes shadow. At night the Earth blocks the sun, and casts a shadow over one entire side of the world.
Light can never be completely gone; there is always some light, though humans may not be able to see it. This is because all matter makes radiation. Complete darkness is only possible at absolute zero.
In mythology, darkness is often connected with evil. Many people are uncomfortable or afraid when in the dark, especially children.