Definition of "sun dog"

December […] the 28th , the Sun being an Hour high, appeared a Sun-Dog or Parhelion, the Sky full of flying Clouds.

1749, Thomas Short, A General Chronological History of the Air, Weather, Seasons, Meteors, &c. […], volume I, London: […] T[homas] Longman, […]; and A[ndrew] Millar, […], page 474

Sun-dogs, called Mock Suns, becauſe they reſemble the ſun, are tvvo ſpots that frequently appear in a cloud vvhen the ſun ſhines through it, and vvhen he is about 15 to 20 degrees above the horizon. […] One is ſituated on the north, and the other on the ſouth ſide of the ſun. The refraction and reflection of the rays of light are the cauſe of theſe phænomena.

1791, Samuel Stearns, “Of the Cause of the Rain-bow, Meteors, Sun-dogs, Jack-with-a-lanthorn, Hurricanes, Trade-winds, Monsoons, Whirlwinds, Water-spouts, Clouds, Rain, Hail, Snow, Frost, Mist, Fog, and Dew— […]”, in The American Oracle. Comprehending an Account of Recent Discoveries in the Arts and Sciences, […], London: […] J[ames] Lackington, […]; and J. Parsons, […], page 167

Two sundogs dread famine bring / A bloody war, and new-crown'd king.

1837 April, F. [pseudonym], “Notices by the Way Side—from Notes Taken in 1821. No. IV. Sacket’s Harbor.”, in The Monthly Traveller, or Spirit of the Periodical Press. […], volume VIII, number 4, Boston, Mass.: Badger & Porter, […], page 146, column 1

The good fog heard—like a splitten sail, to the left and right she tore, / And they saw the sun-dogs in the haze and the seal upon the shore.

1896, Rudyard Kipling, “[The Seven Seas.] The Rhyme of the Three Sealers.”, in The Seven Seas, London: Methuen & Co. […], page 68

Sometimes it is clear, and at midday the sun looks at us for a moment over the hills to the south. The northern lights flame in the sky, and the sun-dogs dance, and the air is filled with frost-dust.

1905, Jack London, “The Sun-dog Trail”, in Love of Life and Other Stories, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., published September 1907 (December 1907 printing), pages 223–224

A sun dog on each side of the sun foretell a bad storm in the night.

1935, Harry Middleton Hyatt, “Weather”, in Folk-lore from Adams County Illinois, New York, N.Y.: Memoirs of the Alma Egan Hyatt Foundation, paragraph 678, page 26

Long understood also, is the fact that sundogs—colored spots of light to the right or left of the sun or moon—belong in the same class with halos.

1941 August 31, “When there’s a ring around the sun”, in John T. Curtis, editor, The Philadelphia Inquirer, volume 225, number 62, Philadelphia, Pa.: The Philadelphia Inquirer Co., “Everybody’s Weekly” section, page 2, column 4

Every rainbow and every sundog remind us, "Yes, you are human and you often fail to live up to God's standards. But God's covenant is eternal, and God loves you nonetheless and not the less."

2000, Michael J. Coyner, “Sundogs and Other Signs”, in Prairie Wisdom: Reflections on Life in the Dakotas, Nashville, Tenn.: Abingdon Press, page 126

Some videos seem to show sun dogs jumping around. […] No one is sure what causes these "jumping" sun dogs. Some scientists think the electric field from lightning in the cloud makes the ice crystals move. When the crystals move, the sun dog moves. But this is just a hypothesis. No one is sure what causes this phenomenon.

2017, Suzanne Garbe, “Sun Dogs”, in The Science behind Wonders of the Sun: Sun Dogs, Lunar Eclipses and Green Flash, Oxford, Oxfordshire: Raintree, Capstone Global Library, page 28