An old habit of mine: Avoid symbol-speaking or abbreviation-speaking. I verbalize "fn" as "function" and "mut" as "mutable" the same way I verbalize "std::unique_ptr" as "standard unique pointer" and not "stid unique pooter".
Edit: Fat arrow?
I don't read code in English, even though I'm a native speaker. So its kindof a silly question: this would only come up when walking someone else through the code. I internally read code using data-flow and control-flow graphs. The written abbreviation is just shorthand for a specific type of graph vertex (or edge).
[1] https://doc.rust-lang.org/book/ch18-01-all-the-places-for-pa...
There is Func<T> - that's a delegate type.
things.Select(thing => thing.Stuff);