Sometimes you may want to have two words be near each other. Generally the closer the words are together the more related the concepts will be. For instance if you are looking for documents that talk about officers of the court, you may want to have the word officer be very close to the word court. However, if you are not getting enough documents that way, you may want to spread the search farther apart, to look for the two words within the same sentence, or maybe the same paragraph.
The farther the distance between the words, the more likely you will get results.
But the nearer the words, the more likely the concepts the words represent are related to each other.
/n
Used to search within a particular number the word. For instance, dog /5 cat will search for documents where the word dog appears within 5 words of cat.
/s
Used to search for two words within the same sentence. For Lexis this is within approximately 25 words of each other rather than actual sentence. Dog /s cat = Dog is in the same sentence (or 25 words) of cat. For Westlaw the two words are actually within the same sentence.
/p
Used to search for two words within the same paragraph. For Lexis this is within approximately 75 words of each other rather than actual paragraph. Dog /p cat = Dog is in the same paragraph (or 75 words) of cat.