ostensive definition

An ostensive definition conveys the meaning of a term by pointing out examples. This type of definition is often used where the term is difficult to define verbally, either because the words will not be understood (as with children and new speakers of a language) or because of the nature of the term (such as colors or sensations). It is usually accompanied with a gesture pointing out the object serving as an example, and for this reason is also often referred to as "definition by pointing." Ostensive definitions rely on an analogical or case-based reasoning by the subject they are intended to.
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Noun
1. a definition that points out or exhibits instances of the term defined
(hypernym) definition

To define something by pointing to something named.  For example, if someone were to say, "What's a baboon?" one might point to one (or to a picture of one, and say "That's a baboon."  Wittgenstein organizes much of his thinking around the concept of an ostensive definition.  Our culture says that ostensive definitions are the major way that children learn language. Wittgenstein's first section of his book, The Philosophical Investigations, shows us why this is an insufficient answer.