Operad theory is a way of studying different ways that things can be combined together. Imagine you have some Legos, and you want to build a spaceship. You can combine the Legos in different ways to make different parts of the spaceship, and then combine those parts to make the whole spaceship.
In operad theory, we think about combining things in a similar way, but instead of Legos, we use different operations. For example, we might have an operation for adding two numbers together, or an operation for taking the derivative of a function.
We can think of these operations as building blocks that we can use to create more complicated systems. The way that we combine these building blocks is called an operad.
Operads are really useful because they let us study how different operations interact with each other. For example, we might want to study how adding two numbers together is related to multiplying them, or how taking the derivative of a function is related to integrating it.
Operad theory also has practical applications in computer science and physics. In computer science, operad theory can be used to study how software components interact with each other. In physics, operad theory can be used to study how particles interact with each other in complex systems.