In grammar, infinitive is the name for certain verb forms that exist in many languages. In the usual (traitional) description of English, the infinitive of a verb is its basic form with or without the particle to: therefore, do and to do, be and to be, and so on are infinitives. As with many linguistic concepts, there is not a single definition of infinitive that applies to all languages; however, in languages that have infinitives, they generally have most of the following properties: