In grammar
In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...

, infinitive is the name for certain verb forms that exist in many languages. In the usual (traditional) description of English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

, the infinitive of a verb is its basic form with or without the particle
Grammatical particle
In grammar, a particle is a function word that does not belong to any of the inflected grammatical word classes . It is a catch-all term for a heterogeneous set of words and terms that lack a precise lexical definition...

 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. Many Native American languages
Indigenous languages of the Americas
Indigenous languages of the Americas are spoken by indigenous peoples from Alaska and Greenland to the southern tip of South America, encompassing the land masses which constitute the Americas. These indigenous languages consist of dozens of distinct language families as well as many language...

 and some languages in Africa
Languages of Africa
There are over 2100 and by some counts over 3000 languages spoken natively in Africa in several major language families:*Afro-Asiatic spread throughout the Middle East, North Africa, the Horn of Africa, and parts of the Sahel...

 and Aboriginal Australia simply do not have infinitives or verbal noun
Verbal noun
In linguistics, the verbal noun turns a verb into a noun and corresponds to the infinitive in English language usage. In English the infinitive form of the verb is formed when preceded by to, e.g...