Let's understand it with an analogy that you want to build a cool toy robot out of LEGO bricks. You start by building the robot's body and head using lots of little bricks, but then you realize that you also need wheels to make the robot move, and a motor to power the wheels. You know how to build those things, but it would take a lot of time and effort to do it from scratch every time you want to make a new robot.

That's kind of like boilerplate code in Ruby on Rails. When you're building a website or app using Rails, you need to set up a lot of things to make it work, like connecting to a database, creating pages, and handling user input. This can be really time-consuming and repetitive. So instead, you can use some pre-written code (just like pre-made LEGO wheels and motors) that takes care of all the boring setup stuff for you. This code is called boilerplate code, because it's like a standard template that you can use over and over again to build your app more quickly and easily.