The point of a definition is to identify the referents of a concept. A definition that does not pick out the right referents- -one that includes too much or too little--is not doing its job.

A definition is too broad if it includes things that are not referents of the concept.

Example:

Humans are two-legged animals.

This definition is too broad because the defining phrase "two-legged animal" includes birds as well as humans.

A definition is too narrow if it fails to include things that are referents of the concept.

Example:

Humans are religious animals

This definition is too narrow because, no matter how widespread religious belief may be, some people are atheists.

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