bokeh
A photographic effect where circular out-of-focus points of light appear in the background of the image.
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).