Let's say, I am writing a dark fantasy book, and there's something called the Three Fingers. The Three Fingers represent a god-like entity that has power over life.
Would it make sense to refer to it indirectly with the number three, since it's three finger as such:
"The power of the Three is beyond imagining."
Or is the word Three too vague to be used as a reference to the Three Fingers? Do I need to explain why Three is a sufficient indirect reference? How can we do so?
I don't think you need to "explain" it really. You have somebody explain (perhaps to a child) about the "Three Fingers", and immediately in the same explanation refer to it as "The Three".
It's how we pick up slang, by the context in which it is used. After all, nobody ever told me explicitly what "Cool" means, I picked it up from the way it was used. People are happy when they say something is "Cool," you figure out it means something like "Great", or "Surprising", or "Interesting", or even "Not alarming". It's all cool, man.
Mention it explicitly, in a teaching or formal context, then quickly refer to "The Three Fingers" as "The Three", and it is all taken care of without breaking any reader immersion.
I can even do it one sentence: "The Three Fingers control our destiny, and the power of The Three is beyond our understanding."
I see this done effectively by arranging a scene in which the relative mythology can be conveyed.
Imagine everyone raising their glass and shouting "l'chaim!"
You may or may not have an earthly clue what's going on. Does this exclamation mean, "to the battle!" or "to life!" or "bottom's up!" or something else entirely?
The 'show' of the action will convey to the reader the importance of the ritualistic tradition. However. Placing a goy in the scene, who is unsure if they should raise their glass or not, allows someone in-the-know to explain what 'l'chaim' actually means and when it is appropriately used and perhaps the history and relevance. In addition, it allows you to establish a relationship between these two characters.
So. You can build your world and characters by leaning into the Three Fingers:
"Three fingers, what is that? An emphatic 'fuck you?'"
She looked at him in horror. "The three fingers trace to our earliest days. The first finger is birth, guided by Gersaina, the goddess of all that is. The second finger is the mortal coil, when the goddess retreats, an absent mother, and allows us to fall on our own. The third finger is the most important of all, the time when we approach death. We choose either to return to Gersaina for another cycle, or we abandon her to endure eternal torment. The three fingers is our most sacred gesture. It is choice and destiny. There is nothing irreverent about it."
