Celeron is a better processor
That is a pretty generalized answer considering that range of celerons available from the first mobile M all the way to the icore based celeron. I agree that probability suggests that he is looking at modern computer or at least something in the past 3 years but I would rather be sure what he is talking about.
Links to what you are considering would be even better. And yes, there are dual core celerons based on the icore architecture. As well as some core based ULV ones. These would all be faster than the atom by far.