Functions of Definitions

Concepts serve as mental file folders that help us organize our knowledge about classes of similar things.

Definitions tell us what is in the folders.

One major function of definitions is to tell us what is and is not included in a concept, by giving us a test or rule for membership. A child who has just learned the concept of PLANT can point to some obvious and clear-cut examples of plants.

A second function of definitions is to clarify the relationships among concepts. Concepts are not isolated, self-contained units; they form networks of interrelated ideas.

A third function of definitions is to provide a summary statement about the referents of our concepts. Definitions help us keep our filing system in order by giving us summary statements about what is in each folder. A good definition condenses the knowledge we have about the referents of a concept, giving us just the highlights, the key points, the essence.


Comprehension Questions

1 Determine which function of a definition is being used in the following instance.

That animal there is not a fish. It is a mammal, even though it lives in the water.

a) determining what is and what is not in a concept
b) clarify the relationship among concepts
c) provide a summary statement about the referents of a concept
2 Determine which function of a definition is being used in the following instance.

Dolphins are not fish; they are a type of mammal.

a) determining what is and what is not in a concept
b) clarify the relationship among concepts
c) provide a summary statement about the referents of a concept
3 Determine which function of a definition is being used in the following instance.

Two characteristics distinguish mammals from all other types of animals. They nourish their young with milk, and they have hair for a body covering.

a) determining what is and what is not in a concept
b) clarify the relationship among concepts
c) provide a summary statement about the referents of a concept


Rules of Definitions

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