A plain old data structure is a way of organizing information, like words or numbers, into neat bundles so that it’s easier to find or use. Imagine you have a cupboard full of your clothes. This cupboard is your plain old data structure – it’s like a box that holds your clothes and organizes them so you can find what you need quickly. Without it, all your clothes would be thrown in a big pile and it would be very hard to find the one you want. Plain old data structures help us organize information and make sure all data stays in the right place.