A parameter array enables a many-to-one relationship: many arguments can be represented by a single parameter array. In other words, parameter arrays enable variable length argument lists.
A parameter array is declared with a params modifier in C#. There can be only one parameter array for a given method, and it must always be the last parameter specified. The type of a parameter array is always a single dimensional array type. A caller can either pass a single argument of this array type, or any number of arguments of the element type of this array type.