bokeh
noun [ U ] art specialized uk/ˈbəʊ.keɪ/ us/ˈboʊ.keɪ/
（摄影）背景散焦效果
a blurred (= not clear) effect used in photography
This lens produces that nice bokeh in the background that looks great in portraits. 这款镜头在背景中产生很好的虚化效果，用于人像摄影非常不错。