It's likely you're thinking of a specific entry or topic. To help me understand what you're looking for, please provide me with more context:
* What is the full name of the encyclopedia?
* Do you remember any other details about the entry? For example, is it a person, a battle, a concept, or a place?
* What is the letter "N" part of? Is it the beginning of a word, part of an abbreviation, or something else?
Once I have more information, I can help you find the meaning of "N" in the encyclopedia.