In the days when the major method of crossing the sea was by sailing ship, the crews developed their own way of speaking.
In this ‘sailor talk’, the term, ‘dog’, meant something that was false or fake.
Today, this old terminology has survived to describe what happens when the sun shines through a thin veil of high, ice crystal clouds.
Sometimes, the sun shining through these thin clouds produces an image of another ‘sun’ on each side of the real sun.
These fuzzy, sometimes colorful ‘fake’ suns are commonly called ‘sun dogs’, a term that has its origin back on the old sailing days. Incidentally, ‘sun dogs’ are often an indication of a change in the weather.