People on Earth can only see one side of the moon because the moon is locked to our planet.

Does the underlined sentence mean 'the moon is part of our planet'? If not, what does this sentence mean?

Omar Ahmedthe moon is locked to our planet.

That's a somewhat odd way of putting it.

The moon rotates on its axis in the same number of days it takes it to go around the earth. I believe there is a special term in astronomy called "tidal locking" that applies to any celestial objects with this property.

You can find a more detailed explanation at the link below.