In grammar, nullar number refers to where nouns take a special form when referring to zero objects. This is similar to how in the English language, one form (the singular) is used for only one object, and another form (the plural) is used for more than one objects. However, in some other languages, e.g. Latvian, there is another form as well as singular and plural, the nullar, used for zero objects. So in Latvian, the singular is used for one object, the plural for more than one object, the nullar for zero objects.

Languages without a nullar get by without one by using either the singular or the plural form for zero. English, along with Germanic and most Romance languages, uses the plural for the zero form. However, French and Brazilian Portuguese usually use the singular instead.