bokeh
Bokeh is an effect in photography (and photography-influenced artwork) where out-of-focus points of light are rendered in the shape of the lens aperture (usually a circle).
Bokeh can represent known light sources in the background of an image, but can also occur in seemingly random places all over the image. The latter, known as orbs, are from light reflected off of particles in the air which would otherwise not be visible.
Lens flare artifacts can look similar to bokeh, but are due to bright light being reflected inside the camera, and don't line up with the original light source (which may not even be visible in the image).
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This tag implicates depth_of_field (learn more).