Bokeh actually comes from the Japanese word for blur or haze: boke. The importance comes in the wider aperture (F stop) setting, that is way the 50mm f1.8 (f.2.8 also works) naturally creates the hazy blurred background, putting the main subject in focus pin point sharp. and the background in bokeh.  The effect can also be achieved by creating a shallow depth of field,  and making the subject further from the background.

The term also comes from the Japanese word for blur quality: boke-aji, and there are a quite a few styles of background blur for a photographic aesthetic which is essentially about being out of focus. The Lomography Petzval lens creates a beautiful swirled bokeh background,  whilst a natural bokeh can come from simply focusing on one part of a subject, the perspective naturally comes into play, for an example check out my food photography

bokeh

All the photography themes for the month are available here, I loved this theme so will be working on more ways to get the most out of the effect.