I have encountered wherein several times in many texts, and the general meaning of the texts was quite evident given the context.
However, I do not know the exact meaning of wherein; a dictionary search returns "How, or in what way; Where, or in which location; During which" (Wiktionary).
But what are the contexts it can be used in, and is there any weird way it is being used sometimes? (I realised by now that English can be tricky.)
Also, are there any differences concerning this word between American and British English (my preferred)?