An extensional definition is one that assigns a meaning to a term by indicating the members of the class that the definiendum denotes.

Three ways of indicating the member of a class: pointing to them, naming them individually, and naming them in groups

Demonstrative (ostensive)definitions

Enumerative definitions

Definition by subclass

Most primitive form of definition

Mostly demonstrated by pointing at an object

Example – “C.S.B. means” that – as you point to it

Assigning a meaning to a term by naming the members of the class the term denotes

Example – “School” means DLSU, ADMU, CSB, or UP

Assigns a meaning to a term by naming subclasses denoted by the term.

Example – “Reptile” means snakes, crocodilians, lizards and the like.

An intentional definitions is one that assigns meaning to a word by indicating the qualities or attributes that the word connotes.

Synonymous Definition

Etymological definition

Operational Definition

Definition by genus and difference

One in which the definiens is a single word that connotes the same attributes as the definiendum

Example – “gender” means sex

Assigns a meaning to a word by disclosing the word’s ancestry to both its own language and other languages.

Example – “captain” is derived from the Latin noun caput which means “head”.

Assigns a meaning to a word by specifying certain experimental procedures to determine whether or not the word applies to a certain thing.

Example – One object weighs “heavier” than another if and only if it has a greater amount of weight according to a weighing scale

Assigns a meaning to a term by identifying a genus term and one or more difference words that, when combined, convey the meaning of the term being defined.

Example – “Puppy”(species) means infant(difference) dog(genus.