I really like the name Arceus, I wish I'd came up with it.

[JaredThaJa888]

I think it is comparable to Tolkien's Iluvatar in the creative etymology that went into it.

Name origin
Arceus's name may come from the words arch (highest) and deus, which is Latin for god. It may also have a root in the Latin word arcanus, which means secret; sacred mystery. Arceus's name may also come from the word archaic (ancient), which comes from the Greek arkhaios, and is derived from the ancient Greek word for "beginning", arkhē. It could have also come from the Latin word archetypus (original). Alternatively, Arceus's name can be seen as a portmanteau of Zeus, the most powerful of Greek gods and arch (highest). Another theory may be the combination of Zeus and Ra spelled backwards (Zeus being the king of gods and Ra being the solar god and creator, albeit in different pantheons). Those two qualities are shared by the Pokémon. Also, Arceus can also be derived from aureus (golden), possibly referring to its hooves and wheel.
Arceus (Pokémon) - Bulbapedia, the community-driven Pokémon encyclopedia

The Neoplatonic Greek Philosopher Plotinus had a concept very very very vaguely comparable to The Trinity

The Demiurge of Neoplatonism is the Nous (mind of God), and is one of the three ordering principles:

Arche (Gr. "beginning") - the source of all things,
Logos (Gr. "word") - the underlying order that is hidden beneath appearances,
Harmonia (Gr. "harmony") - numerical ratios in mathematics.

Logos is obvious, Harmonia in place of The Holy Ghost makes more sense when you look at the Greek Mytholgoy behind it. But what's relevant here is Arche, one of the words likely involved is forming Arceus, which appears to be in the position of The Father.

Deus and Zeus both come from the Proto Indo-European Dyēus (also *Dyēus ph2ter), as does Jupiter, the Vedic Dyaus Pita and others. Also Theos, Dios and Dio, the modern Greek, Italian and Spanish words for God are likely connected.

In modern spelling Deus and Zeus differ only in it's first letter, all 3 they have in common are the last part of Arceus.

[CaptHayfever]

Not "likely connected", definitely connected. The Roman pantheon IS the Greek pantheon, just with new Latin names, and Italian & Spanish are both derived from Latin.

And remember, "I'm-a Charizard, number, well, six."

[JaredThaJa888]

Not in origin, the Roman began identifying their gods with Greek gods after they began having constant contact with Greece.

Some of the Identification where pretty accurate like Jupiter and Zeus. But other where way off like Saturn and Kronos.