Abigail, I would argue that if a cumbersome, obscure word like "anoctothorpe" or "octothorpe" has become supplanted in ordinary usage for decades by a term like "pound sign" or "number sign" or "hash mark" or "square", it is best not to disturb their remains.

Each has died a natural and entirely deserving death and whoever perturbed you by exhuming "anoctothorpe" is doing no-one a service.

Some obsolete words have interesting histories and some bear themselves in repose with grace and dignity.

These words are obscure both in usage and history and they are ungainly to boot.

So let's send these ghastly curmudgeons back to the grave, Abigail. Shall we? :)