This is a very petty nitpick, by the way.

The notebook canonically refers to a "hex" as an instance of casting something (aka a list of patterns), whereas a "spell" is just a type of pattern. However, the mod itself is inconsistent with this convention, both in and outside of the book:

• The spellbook item should be called a hexbook, since its primary use is to store hexes.
• Spell circles should be called hex circles (or maybe just circles?) because a circle casts a hex, not just a spell.
• The term "spellcasting" is used once in the book, not including where it's used to refer to Psi spells.
• This quote: "Patterns themselves, used for crafting magic items and truly mind-boggling feats like spells that cast other spells" should say "hexes that cast other hexes".
• This quote: "Finally, it seems spells have a maximum range of influence, about 32 blocks from my position. Trying to affect anything outside of that will cause the spell to fail." should probably say either "hexes" or "patterns".
• I think the term "spell" is used instead of "hex" in a couple other assorted places in the book.

An alternative might be to rename spells to something else, and rename hexes to spells? It definitely feels more natural, and I know a lot of people use the terms interchangeably for that reason, even though a spell is a different thing in this mod.

I think it might even make sense to swap the terms, since "putting a hex on something" is like a finalizing action or end result? Although the transition would be made much more confusing if it was a direct swap I suppose...
I definitely think we need to free up the word "spells" so that it can be a synonym, even if it's not canonically the right word or only word. It's... kind of confusing trying to explain the terminology to people that are new to the mod. I mean if it needs an FAQ, that might be a bad sign.
Perhaps rename spells to "interactions" or "world actions"? It's not very flavorful but it gets the message across.
On a related note, I think there ought to be a clearer distinction between spells and other actions. Generally speaking, I think spells are things that require ambit on their arguments and which are named for what they do (Per "naming actions": "After all, why call it a Demoman's Gambit when you could just say explosion?"), whereas other actions (arithmetic and such) do not. However, I suppose if that definition is the intent, the raycast distillations (Archer's/Architect's/Scout's) and zone distillations might need a special category, or ambit should be explained better?