BOKEH
In photography, bokeh (/ˈboʊkə/ BOH-kə or /ˈboʊkeɪ/ BOH-kay;[1] Japanese: [boke]) is the creative aesthetic quality of the blur produced by making use of the DEPTH OF FIELD (Click for more information)
to alter out-of-focus parts of an image. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens glass aberrations and aperture shape cause very different bokeh effects. Some lens designs blur the image in a way that is pleasing to the eye, while others produce distracting or unpleasant blurring ("good" and "bad" bokeh, respectively).