Ruby (programming language)
Matsumoto defined it this way in an interview:Ruby is object-oriented: every value is an object, including classes and instances of types that many other languages designate as primitives (such as integers, booleans, and "null"). Variables always hold references to objects. Every function is a method and methods are always called on an object. Methods defined at the top level scope become methods of the Object class. Since this class is an ancestor of every other class, such methods can be called on any object. They are also visible in all scopes, effectively serving as "global" procedures. Ruby supports inheritance with dynamic dispatch, mixins and singleton methods (belonging to, and defined for, a single instance rather than being defined on the class). Though Ruby does not support multiple inheritance, classes can import modules as mixins.
Object (computer science)
Rather than structure programs as code and data, an object-oriented system integrates the two using the concept of an "object". An object has state (data) and behavior (code). Objects can correspond to things found in the real world. So for example, a graphics program will have objects such as "circle", "square", "menu". An online shopping system will have objects such as "shopping cart, customer, product". The shopping system will support behaviors such as "place order", "make payment", and "offer discount". The objects are designed as class hierarchies. So for example with the shopping system there might be high level classes such as "electronics product", "kitchen product", and "book". There may be further refinements for example under "electronic products": "CD Player, DVD player", etc. These classes and subclasses correspond to sets and subsets in mathematical logic.