A definition of a term is a statement of its meaning by enumerating its characteristic attributes.
That the enumeration must be in terms of its distinguishing or characteristic attributes is implied in the derivation of the term definition. The attributes must establish limits or bounds, just as a line fence limits a land owner’s possessions. To indicate that man is a creature possessing the power of locomotion, sense of sight and ability to eat, is surely not a definition, as the marks are not characteristic of men only. These attributes set no boundary between man and horse, consequently the statement is a faulty description of man, not a definition.But when the enumeration includes such attributes as power of speech, rationality and ability to laugh, then does the description become a definition. To put it differently: A definition is a description of a term by means of its distinguishing attributes. This statement may be considered a definition of man, though somewhat faulty: “A man is a creature who is rational and who possesses the power of speech and ability to laugh.”
4. DEFINITION AND DIVISION COMPARED.
We have learned that general terms when connotative may be used extensionally or intensionally.
A definition indicates the intensional nature of a term, while a statement which points out the extensional nature of a term is known as logical division. More briefly: A definition is an intensional statement of the nature of the term, while logical division is an extensional statement of the nature of the term.
To illustrate: The following statements are definitions:
(1) A dog is a domesticated quadruped of the genus canis and given to barking.
(2) A quadrilateral is a rectilinear figure of four sides.
(3) Soil is a substance composed of pulverized rock and decayed vegetable matter in which plants will grow.
The following represent Logical Division: