Bokeh

Bokeh is the effect of the background of the image becoming 'blurred' into little balls. This can be used to bring focus to the main subject of the image, or used artistically to create a dream like effect to the image.

To make an image with bokeh, you need to use a low f stop, which will result in the focal point being in focus and the rest being blurred. If you have a point of light in the image, such as fairy lights, then the light will become blurred into balls. To create different shaped bokeh you need to cut a shaped pin hole into a cover on the lens.