Online games can be played in different modes; either as a single player or multiplayer. Minecraft Server refers to the type of muiltiplayer mode that allows you play as you choose; either alone or with a group of friends. While playing these types of games, you can also make contact with other Minecraft players from a broad selection of online games.
To enable players make changes to different parts of a game, a file has to be included to the server. Minecraft plugins are files that are included in the multiplayer servers for this purpose. There are different types of Minecraft plugins that help players modify various aspects of any game. An example of Minecraft plugin that enables you make these changes is the Dynmap Plugin.