It means "to the sources".
Latin is ano-domini and English is in the year of our lord
To the sources; to the roots.
The phrase 'Ad vitam aeternam' is in Latin. The meaning in English is the following: To eternal life; or, loosely, 'for all time', or 'forever'. The word-by-word translation is as follows: 'ad' means...
to do something so many times that everyone is sick of it