Throughout this document, any Capitalized word refers to a game term with specific mechanical meaning. Those terms are all defined in this document along with other rules necessary for the basics of play. Some terms that aren’t capitalized (like “foe” and “spread”) are also defined in this document in order to clarify game interactions.
The capitalization is done so that you know when something is meant to use a specific mechanic or narrative instead of using that word as part of regular language. For example, a bit of text might say that something burns, meaning it can be lit on fire. But if something says it Burns, then it will cause you to lose a card to the Pyre.
Some of these terms are entirely mechanical (Draw), while others are entirely narrative (Nightmare). Most will be both!