Graphics will almost always have a geometry component which is necessary for placement on the map. These geometry objects can be Point, Multipoint, Polyline, Polygon, or Extent and can be either created programmatically, or returned as the output from a task, such as a query.
Before creating any of these geometry types the required esri/geometry resource needs to be imported. The geometry resource contains classes for Geometry, Point, Multipoint, Polyline, Polygon, and Extent.
Geometry is the base class which is inherited by Point, MultiPoint, Polyline, Polygon, and Extent.
The following example shows how you can create a Point object:
new Point(-118.15, 33.80);
The Point class defines a location by an x and y coordinate, and can be in either map units or screen units.