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+Crafting Guide uses a number of terms throughout its documentation and code which have specific meanings and relationships beyond their general use in the Minecraft community.  This is a brief orientation to how these terms are used within Crafting Guide.
+
+----
+
+### Craftable
+
+An `Item` which may be created from other `Items` using either just the player's 2x2 crafting grid or some other `Tool`. Such items are always associated with at least one `Recipe`.
+
+### Gatherable
+
+An `Item` which may be found, as-is, in the Minecraft world.  Some `Items` can be both `Craftable` and `Gatherable` (e.g., Wool can be found from sheep or made from String).
+
+### Item
+
+A single distinct object in the Minecraft world which may be held in a player's inventory. `Items` may be `Gatherable` or `Craftable` or both (but not neither).  `Craftable` `Items` are associated with at least one `Recipe`.  All `Items` are first declared in a `ModVersion Data File`, and may (optionally) have an `Item Data File`.
+
+### Item Data File
+
+A YAML-based text file which describes extra content for an `Item`. This includes an (optional) list of videos and a markdown description (including images) which describes the item. See [[Item Data File Format]] for complete details.
+
+### Item Group
+
+A collection of like `Items` within a specific `Mod Version`.  These collections are merely for organizational purposes within Crafting Guide and don't relate to any in-game concept or mechanic.
+
+### Mod
+
+An extension to the original Minecraft game which is packaged and downloadable as a single unit. As `Mods` change over time different `Mod Versions` are published. All `Items` and `Recipes` are associated with these `Mod Versions` rather than with the overall `Mod`. `Tutorials`, on the other hand, are associated with the `Mod` itself. Each `Mod` is described by a `Mod Data File`.
+
+### Mod Data File
+
+A YAML-based text file which describes an individual mod. This will generally list general information about the mod (e.g., author, website URL) as well as the `Mod Versions` available and any `Tutorials` for that `Mod`. See [[Mod Data File Format]] for complete details.
+
+### Mod Version
+
+A description of a `Mod` at a specific point in time. As `Mods` change, they often add or remove `Items` and `Recipes`, and a `Mod Version` represents a static picture of one particular release.  `Mod Versions` are declared in a `Mod Version Data File` which lists the `Items`, `Item Groups`, and `Recipes` which are available in that version of the `Mod`.
+
+### Mod Version Data File
+
+A YAML-based text file which describes a `Mod Version`. This contains a list of `Item Groups`, which each contain a list of `Items`, which each contain a list of `Recipes`.  See [[Mod Version Data File Format]] for full details.
+
+### Recipe
+
+A description of how to transform one set of `Items` into another set of `Items`. `Recipes` must always include a list of input `Items`, and a `Pattern` describing how these should be laid out on a crafting grid (or in whatever other tool is used). `Recipes` may also specify the quantity of the `Item` created as well as other `Items` which the recipe yields and their quantities.  Finally, a recipe may also specify any number of `Tools` required.
+
+### Tool
+
+An `Item` which is required by a `Recipe`, but which is not consumed by the recipe (e.g., a Crafting Table).
+
+### Tutorial
+
+A combination of text and images which describes how to use some feature of a `Mod`.  These can be very free-form and include whatever content the author likes. They are associated with each individual `Mod` (rather than the `Mod Version`).  They are described in `Tutorial Data Files`.
+
+### Tutorial Data Files
+
+A YAML-based text file which contains the content of a tutorial. These contain the markdown text of the tutorial itself (including any external links, images, etc.) as well as a list of related videos.  See [[Tutorial Data File Format]] for full details.
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