everyone keeps talking about MCP - what actually is it in normal words

i keep seeing people mention MCP servers (postgres, notion, whatever) and honestly i have no idea what that means. is it like a plugin? do i need to know how to code to use it? i'm using Claude Pro right now just through the web interface and it works fine for my stuff (mostly writing and research). am i missing out on something huge or is MCP just for technical people?