Intel is rebranding their Atom processors to follow the same, simple tiering that the Core i processors use. The Intel Atom chip will now be offered in three tiers: Atom x3, Atom x5, and Atom x7. This follows the same pattern as the Core i3, i5, and i7. Atom x3 is the least capable and Atom x7 is the most capable with the x5 in the middle to balance value and capability. Mostly this should simplify consumer confusion and help strengthen the brand as performance of the x3 tier would not decrease the reputation of the x7 tier.
Intel chips on the consumer side now consists of the Intel Atom x3-x7, Core M, and Core i3-i7. The functionality and capability increases from Atom to Core M to Core i.
For more details, see the Intel InsideScoop post.