In C++, an object is an instance of a class. A class is a user-defined data type that holds its own data members and member functions. It is like a blueprint for an object, defining its attributes and methods. Attributes and methods are variables and functions that belong to the class, often referred to as "class members". When a class is defined, no memory is allocated, but when an object is created, memory is allocated. An object is a runtime entity that has state (data) and behavior (functionality). All the members of a class can be accessed through an object. To create an object of a class, the class name is specified, followed by the object name. The dot syntax is used to access the class attributes and methods on the object. Private and protected members of a class cannot be accessed directly using the dot operator.