docs: add a glossary page to describe some common terms

docs/.vitepress/config/en.ts

@@ -63,6 +63,10 @@ function sidebarGeneral(): DefaultTheme.SidebarItem[] {
         //   text: "Setup Guide",
         //   link: "/general/setup-guide",
         // },
+        {
+          text: "Glossary",
+          link: "/general/glossary",
+        },
         {
           text: "Emulator Support",
           link: "/general/emulator-support-and-issues",

docs/general/glossary.md

@@ -0,0 +1,115 @@
+---
+title: Glossary
+description: Breakdown of terms you might see all around the website
+---
+
+# Glossary
+
+Below is a list of terms used around the RetroAchievements site described to help explain them!
+
+## Award / Badge
+
+Awards, also sometimes referred to as badges, are given for completing various tasks.
+
+There are three different types of awards
+* Event Awards – Given for completing [events](events.md).
+* Game Awards – Given for [completing](#completion) or [mastering](#mastery) game sets.
+* Site Awards – Special awards given out for completing certain tasks
+
+## Cheevo
+
+Short for "Achievement".
+
+## Core
+
+A core, also referred to as a libretro core, is a specific emulator used in RetroArch (or RALibretro) to play a particular game.
+
+For example, you might use the DeSmuMe or MelonDS DS core for Nintendo DS games.
+
+You would manage all of this inside RetroArch and download the cores needed for the games there.
+This is why RetroArch is listed as supporting many systems.
+
+## Completion
+
+Completion is the [softcore](#softcore) version of a [mastery](#mastery).
+
+You earn it for collecting every achievement in a game or [set](#set).
+
+## Developer
+
+Around the site, you'll see "developers" and sets "developed by" users of RetroAchievements.
+These are almost always users of RetroAchievements developing the achievement set, not the game.
+
+Whenever you see someone listed as a "Developer" or "Jr. Developer", they are individuals who develop sets for the site.
+
+## Event
+
+An event is a set of challenges put on by the community to challenge players into doing various tasks for a badge.
+
+See [the dedicated page](events.md) for more information and some active events you can hop into!
+
+## Hardcore
+
+"Hardcore" is a mode for achievement collecting that disables certain emulator features to simulate playing as you would on a real console.
+
+Collecting every achievement in a [set](#set) in hardcore mode gives you a [mastery](#mastery) of the game, and a badge for your profile.
+
+See the [FAQ entry](faq.md#what-is-hardcore-mode) for more information about Hardcore/Softcore mode.
+
+## Mastery
+
+This is when you collect every achievement in a game's set in [Hardcore](#hardcore) mode.
+
+Mastering a game awards you a [badge](#award-badge) for your profile.
+
+## RetroPoints
+
+The "white points" you see next to the blue normal points. A tooltip describes them as the points adjusted for rarity.
+
+See the [FAQ entry](faq.md#what-are-the-white-points) for more information.
+
+## Set
+
+A "set" is a collection of achievements for a game.
+
+Game and set are usually used interchangeably, as many games have one base set, but there are a handful of subsets.
+
+See [what is an achievement set?](how-ra-works.md#what-is-an-achievement-set) for more information.
+
+### Multiset
+
+Multiset is a tool for subsets that allow you to earn achievements towards multiple subsets at once.
+
+See [the dedicated subsets page](../guidelines/content/subsets.md) for more information.
+
+### Subset
+
+A subset is an additional set for a game, containing additional challenges or requirements that are beyond the main game's set itself.
+
+You can see these by going to a game's page and navigating to the other icons above the achievement list.
+
+See [the dedicated subsets page](../guidelines/content/subsets.md) for more information.
+
+## Softcore
+
+"Softcore" is a mode for achievement collecting that allows you to use all of an emulator's features. 
+
+Collecting every achievement in a set, in either hardcore or softcore, gives you a [Completion](#completion) of the game, and a [badge](#award-badge) for your profile.
+
+See the [FAQ entry](faq.md#what-is-hardcore-mode) for more information about Hardcore/Softcore mode.
+
+## Standalone
+
+Typically, all games run on an emulator. However, some games run standalone.
+Currently, there are just Terraria and Final Fantasy XI, but more may be added in the future.
+You'll see these under "Standalone" or "EXE".
+
+Standalone games run as is, without an emulator, and require something else, like a mod, to get you connected to RetroAchievements.
+
+## Ticket
+
+A ticket is a report of an issue with an achievement. You'll see a button for this on the side of game pages.
+
+You may also see them referred to as "reports" or "issues" with the achievements.
+
+See [how do I report a broken achievement?](faq.md#how-do-i-report-a-broken-achievement) in the FAQ for more information about reporting.