Zero is a number denoting the lack of any quantity or measure. In the Hindu-Arabic numeration system, it is denoted by the numeral 0. In algebraic structures, zero is also a name given to an element in an additive monoid, group, ring, or field that acts as the additive identity, such as zero itself (in the context of real numbers), zero vector, zero matrix, and zero function. It is neither a negative or a positive number.