i saw a half moon really bright and saw the same underneath it but dull and lighter what is this called

Question: i saw a half moon really bright and saw the same underneath it but dull and lighter what is this called
- Keywords:
  moon
Asked by 379sptm42 to Angus, Guy on 6 Mar 2018.
- Guy Rixon answered on 6 Mar 2018:
  
  Maybe you saw the part of the moon that was not in direct sunlight? Some light gets round to the dark side by reflecting off the Earth, so it’s not completely dark. If this is not it, could you maybe ask again with some more details?

Question: i saw a half moon really bright and saw the same underneath it but dull and lighter what is this called