Glossary
Terms that recur throughout the launcher documentation, explained in one place.Game and instances
| Term | Explanation |
|---|---|
| Instance (Instance) | A self-contained copy of the game (game files + mods + saves + settings). One instance corresponds to one version directory under versions/ |
| Game directory (Game directory) | Commonly known as .minecraft; the root directory holding game files. The launcher can manage several game directories at once |
| Data directory (Data directory) | Where the launcher stores its own configuration, cache, and logs; separate from the game directory |
| Version isolation (Version isolation) | A mechanism that isolates each instance’s mods, saves, resource packs, and other data so multiple instances do not mix files |
| Complete missing files (Repair files) | Scans an instance for missing game files (libraries, assets, client.jar) and downloads them automatically |
Loaders and modpacks
| Term | Explanation |
|---|---|
| Vanilla (Vanilla) | The official game with no Loader (Loader) |
| Loader (Loader) | A framework that loads mods on top of vanilla: Forge, Fabric, NeoForge, Quilt. Mods for different loaders are generally not interchangeable |
| Mod | A modification that changes game behavior, installed per loader |
| Modpack (Modpack) | A fully preconfigured game environment: game version + loader + a full set of mods + settings, installed in one click |
| Resource pack (Resource packs) | Replaces the game’s visuals and sounds (formerly called “texture pack”) |
| Shader pack (Shader packs) | Works with a shader loader to add lighting and shadow effects |
| Data pack (Data packs) | Vanilla data extensions at the world level; they travel with the save |
| Schematic (Schematic) | A building blueprint file for the Litematica mod |
Accounts and authentication
| Term | Explanation |
|---|---|
| Microsoft login (Microsoft sign-in) | OAuth authorization with a genuine Microsoft account |
| Offline login (Offline login) | Verifies only the username; used for singleplayer or offline servers |
| External login (Yggdrasil) (External login) | Third-party authentication services (such as LittleSkin or Tongyitong) that emulate official verification with their own account systems |
| Tongyitong (Unified Pass) | The name of one Yggdrasil external login service |
Multiplayer
| Term | Explanation |
|---|---|
| Host (Host) | The player who creates a multiplayer room and manages players and the mod list |
| Room code (Room code) | A short code the host shares with friends; it is used to join the room |
| NAT | The address translation type of the router, which determines how easy a direct P2P connection is; strict NAT may require relaying |
| Mod consistency (Mod consistency) | Before joining, the launcher compares the host’s mod list with your local one so the game does not crash over mismatched mods |
Diagnostics
| Term | Explanation |
|---|---|
| mclo.gs | A public log sharing service that turns long logs into short links you can paste into issues or chats |
| JVM arguments (JVM arguments) | Launch arguments passed to the Java virtual machine, often used to adjust memory and garbage collection |