A generalization (or generalisation) is the formulation of general concepts from specific instances by abstracting common properties. Generalizations posit the existence of a domain or set of elements, as well as one or more common characteristics shared by those elements (thus creating a conceptual model). As such, they are the essential basis of all valid deductive inferences. The process of verification is necessary to determine whether a generalization holds true for any given situation.
Generalization is the process of identifying the parts of a whole, as belonging to the whole. The parts, completely unrelated may be brought together as a group, belonging to the whole by establishing a common relation between them.
It must be stated that, the parts cannot be generalized into a whole until a common relation is established among all the parts. But this does not mean that the parts are unrelated, only that no common relation has been established yet for the generalization.
The concept of generalization has broad application in many connected disciplines, sometimes having a specialized context or meaning.
Of any two related concepts, such as A and B, A is a "generalization" of B, and B is a special case of A, if and only if
every instance of concept B is also an instance of concept A; and
there are instances of concept A which are not instances of concept B.
The connection of generalization to specialization (or particularization) is reflected in the contrasting words hypernym and hyponym. A hypernym as a generic stands for a class or group of equally ranked items—for example, tree stands for equally ranked items such as peach and oak, and ship stands for equally ranked items such as cruiser and steamer. In contrast, a hyponym is one of the items included in the generic, such as peach and oak which are included in tree, and cruiser and steamer which are included in ship. A hypernym is superordinate to a hyponym, and a hyponym is subordinate to a hypernym.