From InterfacesShouldBeAdjectives ...

'''Interfaces Should Be Nouns'''

The primary reason to create an interface is to allow for a collection of similar, but different objects.  As a concrete example, if one wanted a collection of Small Dogs, Medium Dogs, and Large Dogs; the obvious interface to create would be Dog.  The adjectives Small, Medium, and Large would be applied when creating the concrete classes Small''''''Dog, Medium''''''Dog, and Large''''''Dog.

An interface is a generalization of a set of classes.  The interface should be a noun.  The derived classes can then be named using Adjective+Noun (such as Small''''''Dog from Dog) or using a more specific noun (such as Dog From Animal).

The use of an adjective for an interface may be appropriate in some situations, such as a decorator pattern.  It is possible one may want a Small wrapper that could take a Dog, Cat, or Fish, but this type of use is much more the exception than the rule.  Use a noun to name an interface as a general rule and only use other naming conventions where an exception is justified.

''Perhaps interfaces should be interfaces ...''

{Discussions in ThereAreNoTypes, AttributesInNameSmell, and PrimaryNoun may take issue with this.}

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CategoryInterface