The term bokeh has been taken from the Japanese dictionary. The term refers to the quality of out of focus effect in an image. You may have noticed the soft out of focus background and foreground. Now, this is referred to as background (and foreground) blur. Bokeh, on the other hand, refers to the quality of the background blur and not just the blur itself.
Additionally, the more the number of blades there are, the rounder will be the quality of bokeh. When trying to achieve bokeh try to have tiny sources of light in the background. That appears like small blobs of circular light in the background. Avoid plain solid backgrounds and keep some space between the subject and the background.