A Canon Pairing is a pairing that either has a basis for existence in the canonical South Park universe. This includes not only currently ongoing relationships, but also one-sided attractions and broken relationships, which still form a canonical basis for shipping purposes.
Though fanon pairings are more popular among dedicated fanfiction writers and fan artists, canon pairings have the unique distinction of having appeal outside the fandom and spurring discussion among casual fans, and this sometimes awards them a strategic advantage in creating and receiving fan works.
During the twentieth and twenty-first seasons, all of the ongoing relationships among the fourth graders were broken at some point (primarily but not exclusively in "Skank Hunt") though many of them have been referenced in later works.
In addition, some fans consider the Egg Couples as canon ships, as they have a canon basis and were selected by Matt and Trey; however, it is still a school project with no romantic background.
The staff of this wiki have elected not to tag 'canon pairings' as to avoid fandom controversies.