"Meteorites are very big, rocky masses that hit the Earth and leave a crater as a souvenir." - We were all right at the same time, with a small misunderstanding.
Well, I feel obligated to defend honor of us all. So I will try to put it in few lines :)

1. Meteoroids - all sizes; when they enter the atmosphere they are meteors>
2. Meteors are objects that were small meteoroids that burns out in the atmosphere.
3. Meteorites are actually larger meteoroids that lose a large amount of mass but still some piece gets to earth, ranging from one millimeters to big chunks that made mass extinction of dinos.
   4)Fireballs are meteors that go into the atmosphere too steep so they burn out and explode with a bang (you can google: Tunguska event)
   some small meteorites
   image taken from planetbrey.com/meteorite_images/pultuskpeas_thumb.jpg
   All the best ;)