"Isometric" refers to the style of the 3D viewpoint. The x and y axis are presented at a 45° angle, and the camera looks 'down' on the surface diagonally.

Escher's work is an example of how an isometric perspective can be manipulated to present an impossible object, such as a staircase that appears to go upwards even though the 'top' stair is connected to the 'bottom'.

Isometric view refers to the way in which 3D objects are represented on a 2D plane. This is the most preferred view in drawing building plans and the like. The other method is called Perspective view in which parallel lines on a 3D object converge to a point on the 2D representation. For e.g., a long-shot picture of a straight railroad track. This is what we usually see in pictures, paintings and the like.