This is not apostrophe (no, not that kind of apostrophe) or anagnorisis; this is when a character communicates a exposition on some aspect of the story's background or context (e.g. how FTL travel works; why the families are at war) ostensibly to another character (often a foreigner or recluse) but actually in place of simple omniscient narration.
I'm not criticizing the practice; I just want a word for it.
Thanks in advance
Best Answer
What you're describing is expository dialogue.
More colloquially, it's also called an info dump or "as you know, Bob" dialogue.
The last term is generally used in a critical sense, referring to dialogue in a movie or tv show that is obviously unnatural and presented only for the audience's benefit. For example: