A Minecraft realm is a multiplayer service provided by Mojang, the company behind Minecraft. It allows players to create and join private worlds that are hosted on Mojang's servers. Realms are easy to set up and manage, making them a convenient option for players who want a hassle-free multiplayer experience. They also offer cross-platform support, meaning players on different devices can play together. On the other hand, a Minecraft server refers to a player-hosted multiplayer world. Unlike realms, servers require players to have their own hardware or rent server space from a hosting provider. This gives players more control over the gameplay experience, as they can customize the server settings and install mods or plugins. Servers are often used for larger communities or specific game modes like survival or creative. So, while both realms and servers provide multiplayer experiences in Minecraft, realms are hosted by Mojang and offer simplicity and convenience, whereas servers require more technical knowledge but provide greater customization options.