Learn in the textbookDesign and Analysis Methods and Modeling
DefinitionObject orientation (オブジェクト指向) is an approach that builds a system from objects, each bundling data together with the operations that handle that data.
ExplanationThe template for an object is called a class, and the objects that actually run are created from classes. Typical properties are encapsulation, which hides the inside from the outside; inheritance, which passes a higher class's characteristics down; and polymorphism, where objects respond to the same instruction in their own ways.
AnalogyYou can use a TV remote just by pressing its buttons, without knowing the circuits inside. Wrapping up the inside and showing only the controls is what makes it like an object.
Memory hookThe word encapsulation comes from a capsule, like a medicine capsule: the contents are sealed inside a shell.