Bokeh refers to the aesthetic quality of the blur you see in the out-of-focus parts of an image, and is produced by the lens. It’s the way a lens renders out-of-focus points of light.
An example of the aesthetic quality of the blur is when the quality of blur is pleasing to view, with an element of smoothness to it.
It is the combination of quality and reflected points of light which photographers refer to as Bokeh.
Bokeh, may also include sharper edges and with a less pleasing quality and smoothness. Some photographers will debate if this is truly Bokeh, however.