Stipulative Definition

Alice Through The Looking Glass
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean–neither more nor less.”. Andrew_Howe/Getty Images

A stipulative is a definition that assigns meaning to a word, sometimes without regard for common usage.

The term stipulative definition is often used in a pejorative sense to refer to a definition that appears to be deliberately misleading. 

Examples and Observations:

"A lexical definition, such as one that occurs in a dictionary (a 'lexicon'), is a kind of report on how language is used. A stipulative definition proposes ('stipulates') that language shall be used in a given way."
(Michael Ghiselin, Metaphysics and the Origin of Species. SUNY Press, 1997)

"Words in a language are public instruments for communication in that language, and a stipulative definition is useful only if it sets out predictable and comprehensible standards of use that are workable for the purpose at hand. If a stipulated definition becomes popular, the word defined in its new sense then becomes part of public language, and it is open to changes and variations in use just as other words are."
(Trudy Govier, A Practical Study of Argument, 7th ed. Wadsworth, 2010)

Misuse of Stipulative Definitions

"Stipulative definitions are misused in verbal disputes when one person covertly uses a word in a peculiar way and then proceeds to assume that everyone else uses that word in the same way. Under these circumstances that person is said to be using the word 'stipulatively.' In such cases the assumption that the other person use the word in the same way is rarely justified."
(Patrick J. Hurley, A Concise Introduction to Logic, 11th ed. Wadsworth, 2012)

Humpty Dumpty's Stipulative Definitions

“There’s glory for you!”

“I don’t know what you mean by ‘glory,’" Alice said.

Humpty Dumpty smiled contemptuously. “Of course you don’t–till I tell you. I meant ‘there’s a nice knock-down argument for you!’”

“But ‘glory’ doesn’t mean ‘a nice knock-down argument,’” Alice objected.

“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean–neither more nor less.”

“The question is,” said Alice, “whether you can make words mean so many different things.”

“The question is,” said Humpty Dumpty, “which is to be master–that’s all.”

Alice was too much puzzled to say anything; so after a minute Humpty Dumpty began again. “They’ve a temper, some of them–particularly verbs, they’re the proudest–adjectives you can do anything with, but not verbs–however, I can manage the whole lot of them! Impenetrability! That’s what I say!”

“Would you tell me, please,” said Alice, “what that means?”

“Now you talk like a reasonable child,” said Humpty Dumpty, looking very much pleased.

“I meant by ‘impenetrability’ that we’ve had enough of that subject, and it would be just as well if you’d mention what you mean to do next, as I suppose you don’t mean to stop here all the rest of your life.”

“That’s a great deal to make one word mean,” Alice said in a thoughtful tone.

“When I make a word do a lot of work like that,” said Humpty Dumpty, “I always pay it extra.”
(Lewis Carroll, Through the Looking-Glass, 1871)

Persuasive Definitions

"Stipulative definitions that slant or bias meanings are called 'persuasive definitions.' They are meant to persuade and to manipulate people, not to clarify meaning and encourage communication. Persuasive definitions are sometimes encountered in advertising, political campaigns, and in discussions about moral and political values. For example the definition, 'A caring mother is one who uses Softness brand disposable diapers,' is persuasive because it unfairly stipulates the secondary designation 'Softness user.' The term 'caring mother' is much more significant than that!"
(Jon Stratton, Critical Thinking for College Students. Rowman & Littlefield, 1999)

The Lighter Side of Stipulative Definitions

Nancy: Can you, like, define the meaning of love?
Fielding Mellish: What do you . . . define . . . it's love! I love you! I want you in a way of cherishing your totality and your otherness, and in the sense of a presence, and a being and a whole, coming and going in a room with great fruit, and love of a thing of nature in a sense of not wanting or being jealous of the thing that a person possesses.
Nancy: Do you have any gum?
(Louise Lasser and Woody Allen in Bananas, 1971)

Also Known As: Humpty-Dumpty word, legislative definition