"Do you mean that evening?"
Translation:Meinst du den Abend?
The hints for "that" are: so, daß, and dies-. I am still not clear about when forms of "the" are translated as "this" or "that" and the usual words for "this" or "that" are not accepted. I do understand that daß is a conjunction and is wrong to use in other circumstances now.
Meinst du diesen Abend is also accepted as a valid answer, and I read in some comment that the dies/diese/dieser/etc thing is used to specify, or express a preference, e.g. THIS evening INSTEAD of tomorrow night. Perhaps that is the way to differentiate those two things, but I confess I'm just speculating.