Help:Contents
Disambiguation
For article names that are both a song and a halo, such as Sin, there exists a disambiguation page at Sin, the song article at Sin (song), and the halo article at Sin (halo).
Instead of typing out [[Sin (song)|Sin]] every time you want to link directly to the song article, a shortcut is [[Sin (song)|]]. The empty second parameter makes the link show the article's name without its last word, in this case (song).