I learned a while back that Miercoles is a minced oath in Spanish. As in, you start to say the other thing that starts with Mier--, make eye contact with a child, and say the other thing.

The same exists in French with Mer...credi

I can confirm, my wife uses this all the time

I think you may need to review what that word means in case you have an incorrect belief about its definition. Almost all notation ever created has a reason or a system, I have no idea why one would think its ultimately arbitrary (having no reason or system).

Consensus is not arbitrary either, that's a strong reason, a lack of arbitrary-ness. Even the second definition of arbitrary, something done unilaterally, is contra-consensus.

Isn’t it possible thst there could be multiple , equally systematic, candidate notations. Isn’t the decision as to which one gains traction arbitrary?