It's also a perfectly fine English word - for the specifics see e.g. https://www.merriam-webster.com/dictionary/null
The problem is that it is not the game's proper name.
The Persians have two champion cavalry archers:the Babylonian Scythed Chariot and the Bactrian Heavy Cavalry Archer.
As far as I can tell from the structure tree, they have the exact same stats. Why do the Persians have (from a gameplay perspective) the same unit twice? Is there a reason for that or am I missing something obvious?
Latest version of the game includes differentiation for cataphracts and chariots, but I agree it does not go far enough. We need trample component and secondary attacks.