You probably hear the word bokeh photography and don't know what it means. It has become quite popular in the last few years. The word bokeh is a Japanese word that means blur. Bokeh photography is where the parts of a photo are out of focused or blurred.
It occurs to parts of the photo that are out of the depth of field range. But it's not just the background image that is a bokeh. It's the light reflections and the images they create, which are usually circular.
Generally, "good bokeh" is where the blurriness is softer and not harsh lines.
Do you like shooting bokeh?
Sources:
Wikipedia,
Photography Life