LATIN DICTIONARYLexicon Latīnum
adverb

ex tunc

ex tunc (not comparable)
Classical[ˈɛks ˈtʊŋk]Ecclesiastical[ˈɛks ˈtuŋk]

Meaning

  1. Late Latinnot comparablefrom then on, from that time
  2. Late Latinnot comparablefrom the beginning, from of old
    Priora ex tunc adnuntiavi, et ex ore meo exierunt, et audita feci ea.I have declared the former things from of old, and they have gone out from my mouth, and I have made them heard.c. 347 CE – 420 CE, Hieronymus, Vulgate Isaiah.48.3

Origins

From ex (“from, out of”) + tunc (“then, in the past”); the use of ex with adverbs of time is a Late Latin development.

Quick answers

What does ex tunc mean in Latin?
ex tunc, a adverb, means “from then on, from that time; from the beginning, from of old”.
How do you pronounce ex tunc?
In classical Latin, [ˈɛks ˈtʊŋk]; in ecclesiastical (church) Latin, [ˈɛks ˈtuŋk].