Google is your friend - https://en.wikipedia.org/wiki/List_of_WLAN_channels
Ce or Ceee mean centre channel plus next channel (or channels).
So 2412 Ce would be 2412 + 2432 - note on 2.4GHz we recommedn only 1 (2412), 6 (2437) & 11 (2462) with 20Mhz Channel widths to avoid overlapping coverage in busy sites with more than 1 AP.
Some devices also do not play well on 40Mhz so if you are running a public site try and disable extension channels.
On 5GHz AC 5210 Ceee uses 5170-5250 MHz, 5290MHz Ceee uses 5250-5330 so you can see adjacent chnnels do overlap just a little.
Setting your Wireless to the correct Country should show in bold the available channels for you on RouterOS, using Regulatory Domain will also ensure you keep your power and frequencies legal too.
Hope this helps
MTCNA, MTCWE, MTCRE, MTCTCE, MTCSE, MTCINE, Trainer
Mikrotik Distributor - New Zealand