De or het classisvergadering?

The correct Dutch article is:

de classisvergadering

Rule Words ending in -ing: almost always de. See the rule

How to use classisvergadering

the classisvergaderingde classisvergadering
this classisvergaderingdeze classisvergadering
that classisvergaderingdie classisvergadering
our classisvergaderingonze classisvergadering
your classisvergaderingjouw classisvergadering
every classisvergaderingelke classisvergadering
which classisvergadering?welke classisvergadering?
a big classisvergadering / the big classisvergaderingeen grote classisvergadering, de grote classisvergadering