Quoted By:
Sinnoh = 神奧
神 is a compound of 申, a bolt of lightning, and 示, a memorial tablet used for rituals, together represting gods, divinity, it's used in Shintō, the main religion of Japan (path of gods).
奧 is two hands storing rice inside a house, later shifting to representing something secluded, mysterious, obscure.
Together, they represent how Sinnoh is the seat of gods and veiled by myth.
Unova (Isshu) = 一種
一 is a singular stroke meaning "one".
種 is a combination of 重, a man carrying a heavy load, and 禾, a grain stalk. Together, they mean seed, possibly because the seed, a coat created by the mother plant, "carries" the child embryo baby plant. Just like in English, seed also means kin, race.
一種 represents how all the creatures of the Pokémon world, despite their physical and ideological differences, are all of the same race and ultimately have something in common. Perhaps a reference to the creation theory from the Canalave library, where it was confirmed that humans and Pokémon once could breed together.
Ransai (Pokémon Conquest) = 亂世
亂 represents two hands tying or organising tangled threads later meaning "chaos".
世, the top of the original 枼, is a leaf, which later came to mean generation or epoch, like the successive foliages of a tree.
In a Japanese context, 亂世 is a literary term for a period of unceasing conflict, and is used to describe the Sengoku period, which lasted for around two hundred years in the 15th and 16th centuries until the three Great Unifiers ushered in the Edo period.