What do the letters ME mean in a date as opposed to AD?

Answer 1

They go like this:
BC or BCE = Before Christ, or Before the Common Era
AD = Anno Domini or After (Christ's) Death
ME = (relating to dates) Middle English, Mesopotamian Era
or Modern Era - which is approximately the same as AD
Hope this helps.

Answer 2

"Modern Era". It means the same thing as AD (anno Domini) but eliminates the religious reference to the (erroneous) birth year of Jesus Christ.