 An ostensive definition can bring about an essential enrichment of a language. The ostensive definition of ‘Charlie’ enriches the language with a name of a particular insect, and it could well be that before the enrichment the language lacked resources to denote that particular insect. Unlike other familiar definitions, ostensive definitions can introduce terms that are ineliminable. (So, ostensive definitions can fail to meet the Eliminability criterion explained below; they can fail to meet also the Conservativeness criterion, also explained below.)