Mormon was the father of Moroni. Mormon was the one who was tasked with compiling what becomes The Book of Mormon. He took many different records and edited them Readers Digest style onto the "golden plates." Along the way he adds his own comments, including the Words of Mormon near the middle, when he is about to change the main source of his material.
When he is done compiling the record of the Nephites, he finds he has some room on the plates, so he adds the record of the Jaredites, which becomes the Book of Jared.
After that he adds his own comments about the church structure in what becomes the Book of Mormon. When he is close to death, he gives the record to his son Moroni. Moroni adds a few comments of his own.
Moroni hides the plates. He later appears to Joseph Smith and eventually gives them to Joseph to translate. The whole collection (minus the 116 pages mentioned in the article) becomes the Book of Mormon.
Hence the nick-name.
Can't believe you didn't know that, RNMomof7...