Some concepts are broader than other concepts. ANIMAL is broader
than DOG because there are other kinds of animals besides dogs.
If all the referents of one concept are included in another, but
one concept refers to more things than the other, then the
broader concept is called the genus, and the narrower one is
called the species.
If a species is a file folder, a genus is a file drawer
containing many folders.
ANIMAL is the genus, and all the different kinds of animals, such
as DOG and CAT, are species of this genus. This is so
because all the referents of the concept DOG are included in the
concept ANIMAL, but the concept ANIMAL refers to more things than
Abstract and Concrete