Word of the day: 'bokeh', Japanese for fuzzy/blurry, and borrowed in English for the aesthetic quality of out-of-focus areas in photographs and film, most notable when shot with a narrow depth of field.
The term appears to be quite recent, so can't be found in classic filmmaking or photography books. But a quick web search reveals this elusive quality to be a hotly debated issue among photography geeks. There is good and bad bokeh, too, dependent on the specific feel of the blur and the shapes that points of light make. One term for an undesired kind of blur is 'nisen bokeh', 'cross-eyed' or 'double-lined' blur.
Not sure how to rate the bokeh of this one...
For the optic theory behind this lense behavior, see 'Understanding Bokeh'.