Object Oriented Programming, or OOP for short, is a computer programming model that focusses on objects, such as scripts, classes, and literal game objects, instead of only functions and logic.
In Unity, components, monobehaviours and game objects all inherit from the Object type, and almost all logic is organised into, or around objects.
Alternatively DOTS, the Data Oriented Technology Stack, provides a suite of tools that process logic separately to objects. This can be more efficient for processing a large amount of data, such as the positions of many objects all at once, without needing to access them individually.