Let's say that in the beginning of your story you mention key terms and/or names of events, ie, "The Accident", should you explain those terms and events immediately (at least within the next few pages----or next few chapters?) Or is it okay to not explain them until like 1/2 through the book...or even until almost the very end? Or perhaps not at all (by this, I mean that you wouldn't have to explain it because readers could abstractly come to a conclusion what the event could have been)? Or does it not matter, as long as my readers get "answers" by the end of the story? (obviously I would pace the story out so that I don't do large amounts of "info dumps")
It's usually entertaining when events are slowly hinted at throughout a story, until the reader has enough information to piece it together. It's natural, as there's no infodumping, and fun, as you have to figure out what actually happened. Of course, that really depends on how critical the event is and how much baring it has on the story. It's really up to your intuition. But I'm guessing from the latter part of your second paragraph that you considered this to be a viable venture, so I recommend it.
Hinting at things is good... spending an entire book hinting at something that turns out to be no big deal when the big reveal comes at the end is bad. I would consider how important it is for the reader to not be given the information. The less important the info the earlier I would reveal it.
I believe that the reader should understand what's relevant to the perspective characters as soon as possible. That's not the same as explaining everything the characters know, and that doesn't necessarily mean explaining directly to the reader. But if something is general knowledge among the perspective characters, and it affects what the characters do and why they do it, the reader should have enough of a grasp of it to understand the characters' choices and root for or against them. (For instance, Wreck-It Ralph takes a while to explain "going Turbo" because that's not a big part of Ralph's motivations, but it sets up pretty quickly what Ralph's situation is and why he wants something more.) Of course, I specify "perspective" for a reason. A lot of stories get away with having a Watson as the perspective character, someone who knows relatively little about the situation and learns things around the same time the readers do. Since the reader understands their motivations and goals, they can provide a good window into what would otherwise be a strange and confusing world.
I think it better to slowly show it throughout the story, and never really give the reader any explicit pointers as to what happened. In a now abandoned project about a drought, I never explained what or how it happened. I showed it by having the adults react with awe when they saw running water, and I showed the duration of the drought by having the children wonder what running water is. I should really get back to that project.
I would suggest reading A Clockwork Orange by Anthony Burgess (for the purposes of this exercise I do mean reading, not watching, although the movie is also excellent) and using your experience as a reader as a meta-guide for which terms you want to explain in your own work and which you can let the reader figure out. Burgess uses a lot of Russian-derived slang words of his own translation/invention, basically leaving the reader to sink or swim through the jungle of new vocabulary. I couldn't have made it through the book without my Russian/English dictionary in my lap, but I have friends for whom figuring out the new words was half the fun. Respecting your readers enough to let them figure things out on their own can sometimes make for the most engaging writing, as long as you drop enough hints along the way that you don't just leave readers puzzled. The amount of explanation is going to depend heavily on your audience, though--you'll need to explain a lot more in a book for 10-year-olds than you will in a book for adults.
