A cour is a season
Anime is broadcast in cours of twelve or thirteen weeks, and the site counts them the way the studios and the fans do: a twelve-episode cour is a season, a split-cour show has two season pages, a long shonen has its arcs. Attack on Titan's final season comes in parts; One Piece keeps the continuous numbering fans use across its arcs, so episode 1100 is episode 1100.
Films between the arcs
A film that continues a series sits on the movies shelf with its year, so Demon Slayer: Infinity Castle lands after the Hashira Training arc and the Naruto films between the Shippūden arcs. The franchise films shelf gathers them.
Where a TV app disagrees
A service sometimes groups the same run differently; match by the air date on the season page, because the number may differ and the date does not. The seasons and episodes page has the rest.
