The Moon receives an equal amount of sunlight on each side, during the lunar day.
The dark side of the Moon refers to the side opposite to the one we see. Since the Moon is tidally locked to the Earth, we only ever get to see one side of the Moon from our vantage point on Earth.
The descriptor “dark side” suggests that darkness perpetually covers the surface of one side of the moon. While it’s true that some part of the moon is dark at any particular time, it’s not always the same part.
A more accurate term to describe the side of the moon we see is the near side. The side opposite the near side is the far side.