What does "I Ship Nalu" mean?
Wait, I know what it is now based on Oded's comment. NaLu is the term fans use for wanting Lucy + Natsu to get together and based off Wikipedia it is safe to say that this is a Portmanteau.

Definition:


  A combination of two (or more) words or morphemes, and their
  definitions, into one new word.


Thanks, Oded. :)