Difference between Isometric, Oblique and Orthographic Drawing

Isometric
It is a method of visually representing three-dimensional objects in two dimensions, in which the three coordinate axes appear equally foreshortened and the angles between any two of them are 120 degrees.


Oblique
It projects an image by intersecting parallel rays from the three-dimensional source object with the drawing surface (projection plan).


Orthographic
It is a means of representing a three-dimensional object in two dimensions. It is a form of parallel projection, where the view direction is orthogonal to the projection plane, resulting in every plane of the scene appearing in affine transformation on the viewing surface


(All texts adapted from Wiki)
(All pictures adapted from Google Images)