In what parts of search eninge NLP might be used, and what kind of NLP?

I'm interviewing for the position on a search engine at e-commerce: "Back End Engineer: Search, Catalogue, NLP".

I want to be as prepared as possible for interview, so, I'd be grateful, if you can point to:

1. Where NLP might be used at search engine?
2. What kind of NLP would it be?

Thanks