What is a referee in the manuscript submission process?
Yes.

A "referee" in an academic context is


  An expert who judges the manuscript of an article or book to decide if
  it should be published.


You should make sure to find established researchers who are capable of judging your manuscript and who do not have conflicts of interest (e.g., frequent collaborators).

This canonical question may be helpful: What does the typical workflow of a journal look like?. Or the peer-review tag (although peer review is somewhat more general than manuscript refereeing).