Don't know about the leopard and model x, but at least in the case of OpenAI luna > Terra > Sol > Astra is a pretty obvious size progression.

But I come from a latin language background, so maybe I'm a bit biased there.

Astra > Sol > Terra > Luna seems clear enough to me

Leopard (10.5) and Yosemite (10.10) both came with clear version numbers

Model X and Model Y are siblings which do not have a clear hierarchical relationship

Gemini 4 Carbon and Gemini 4 Argon are rather difficult for me to tell at a glance

Luna/Terra/Sol/Astra make perfect sense, it indicates model tier/size with larger celestial body representing larger model.

Same for Anthropic, consistent model tier naming reused across model generations.

Those are just like i3/i5/i7 or M-series Pro/Max/Ultra.

But Carbon seems to be full replacement of Argon announced two weeks ago, they're same price. So Argon doesn't mean anything, they just picked random element.

FYI, Model S, 3, X, Y is an acronym for S E X Y.

Would it have been so hard to call it Gemini 4.1 or 4.5?

terra/sol or opus/haiku give an indication of size (the sun is bigger than the earth, opus is larger than a haiku). Carbon is smaller than argon (periodic table speaking), so that's no longer a helpful way of thinking about the model sizes...