>The Japanese name is a portmanteau of Shin'ō and Jōto, as it is a place where the architecture and legends of both regions meet. The English name reflects this, though using the beginning of "Johto" rather than the end. The combination of the names of two regions alludes to the Tohjo Falls.
>It may also be a pun on the Japanese native religion of Shinto, whose creation story is heavily referenced by the creation trio, Arceus, and the Spear Pillar.
Bulbapedia/ Sinjoh Ruins