MC Terminology

• Minecraft - The game this page is about. Unless specified, I'm usually refering to Minecraft: Java Edition
• Mojang - The company that owns and develops Minecraft
• Microsoft - The parent company of Mojang. Note Microsoft is NOT Mojang.
• Java Edition - The Original Minecraft, Minecraft for Windows, MacOS and Linux, made using Java. Unless specified, I'm usually refering to Minecraft: Java Edition
• Java - The programming language used for Minecraft Java Edition.
• JVM - A program/Virtual Machine that runs Java bytecode, which in turn runs Minecraft: Java Edition.
• JVM Arguments - Refers to arguments sent to the JVM, these are usually used for stuff like setting min(-Xms512M) and max(-Xmx4G) ram usage
• Java Classes, Objects, Fields, Methods. - Refer to Java Object Oriented Programming at W3Schools
• .jar - A Java Archive, basically a "special" zip used by Java that usually contains code or assets.
• RAM - Also refered to as "Memory". Used by programs and your computer for temporarily storing things like text, images, etc. It's hyper fast compared to other forms of storage but can't hold onto data after losing power. Minecraft usually requires about 4-8 gig to be allocated. Due to how Java handles garbage collection(Cleans memory of unused things), more than 8 gig allocated can either cause lag or cause the game to use far more memory than it should.
• Bedrock Edition - Minecraft's cross platform release. Has a bunch of differences from Java Edition. Refer to Minecraft Wiki's parity list for a compilation of ALL of the changes
• Behavior Pack - Sorta like Minecraft Data packs, I think. I don't play Bedrock Edition so I don't entirely know. These do NOT exist on Java Edition
• Addon - Kinda like Mods, I think. I don't play Bedrock Edition so I don't entirely know. These do NOT exist on Java Edition
• Launcher - Refers to the program used to launch the game, Minecraft requires a launcher because it needs a lot of maintenence,
• Client - The actual program you interface with to play the game. Basically it handles the GUI, displaying mobs, players, blocks, etc on the screen, and stuff like that.
• Server - The program that's running the world you're playing on. Handles things like breaking/placing blocks, movement, mob activity, etc
• Past Minecraft Release 1.3.1, You will always be playing on a server. When in SinglePlayer, Minecraft will open an Internal Server and join it. This is what allows you to play using LAN
• LAN - Local Area Network refers to playing with other people on the same home internet, or together via an ethernet hub. Note that in many cases a LAN server is usually just a server that isn't port forwarded(For Minecraft atleast)
• Port Forwarding - Port fowarding basically tells your router to redirect any communications on a port(like 25565) to a specified IP
• IP/IP Address - An address to access your computer from like 192.168.0.106. Many IP Addresses are reserved for specific use cases.. Relevant to Minecraft, 10.0.0.0–10.63.255.255 and 192.168.0.0–192.168.255.255 are usually used for LAN, 10.0.X.1/192.168.X.1 are usually used by routers, and 127.0.0.0-127.255.255.255 are reserved for loopback/localhost. Minecraft mostly only uses IPv4. IPv6 IP Addresses will usually work but are rarely used
• Resource Pack - A file or folder that edit's the clients resources. Usually replaces things like textures, names, models and sounds.
• Texture Pack - Outdated term that usually refers to a resource pack nowadays, Minecraft stopped using the term Texture Packs around 1.5
• .minecraft - Refers to the folder where the game's files are located.
  
Using the default Launcher, these are located under
• %appdata%/roaming/.minecraft for Windows
• ~/Library/Application Support/minecraft for MacOS
• ~/.minecraft for Linux
• Other launchers will use different locations for your .minecraft, for example, Prism's portable install will store game files under Prism/Instances/INSTANCE/minecraft
• Instance - A setup for Minecraft, usually specifies the location of the game's .minecraft, what ModLoader to use, it's JVM arguments, etc
• Modloader - A modification to the game's jar file that allows the game to load mods. Usually from .minecraft/mods
• Forge - A Minecraft Modloader, commonly used for larger content mods and/or versions below 1.13.
• NeoForge - A Minecraft Modloader based off of Forge, commonly used for larger content mods on versions newer than 1.20.2.
• Fabric - A Modloader for Java games, commonly used for smaller mods and/or versions above 1.13.
• Mod - A file(usually a jar) that gets loaded by a ModLoader to edit or add to the game. Mods usually edit the game's code, provide a custom datapack, assets and more.
• Mixin(s) - Allows mods to almost directly edit game code at runtime.
• Shaders/ShaderPack - A zip that usually adds effects to Minecraft like better shadows or reflections. Requires a mod that provides support for Shaders like Iris or Oculus
• OptiFine - The old go-to mod for performance. OptiFine has been mostly been replaced by stuff like Sodium. Refer to the OptiFine part of the next section for why I and much of the community recommend against OptiFine for newer versions of Minecraft
• Spigot - A modification to Minecraft's Server jar that loads plugins and extends the base server with a mostly version independant API
• Plugin - A jar file that gets loaded by a Plugin Loader like Spigot or Purpur to add to a server through an API. Plugins do not directly modify a server unlike Mods
• They can only be used on servers and can only do server sided things like adding functionality to commands or items.
• They are unable to directly add items, blocks, etc
• Due to how Bukkit, Spigot, Paper, Purpur, etc work, plugins will usually work between versions unlike mods, however massive changes(e.g 1.13 flattening or 1.20.5's components) usually cause SOME issues
• Purpur is a fork of Paper- which is a fork of Spigot which is a fork of Bukkit. Purpur can load most Paper, Spigot and Bukkit plugins however Spigot is unable to load Paper or Purpur plugins.