"A sun dog or sundog (scientific name parhelion, plural parhelia, i.e. "beside the sun") is a common bright circular spot on a solar halo. It is an atmospheric optical phenomenon primarily associated with the reflection or refraction of sunlight by small ice crystals making up cirrus or cirrostratus clouds. Two or more sundogs can often be seen on opposite sides of the sun simultaneously." ~Wikipedia

Whatever you call it it's gorgeous. :)