| sun | <botany> See Sunn. 1. The luminous orb, the light of which constitutes day, and its absence night; the central body round which the earth and planets revolve, by which they are held in their orbits, and from which they receive light and heat. Its mean distance from the earth is about 92,500,000 miles, and its diameter about 860,000. Its mean apparent diameter as seen from the earth is 32' 4<sec/, and it revolves on its own axis once in 25 1/3 days. Its mean density is about one fourth of that of the earth, or 1.41, that of water being unity. Its luminous surface is called the photosphere, above which is an envelope consisting partly of hydrogen, called the chromosphere, which can be seen only through the spectroscope, or at the time of a total solar eclipse. Above the chromosphere, and sometimes extending out millions of miles, are luminous rays or streams of light which are visible only at the time of a total eclipse, forming the solar corona. 2. Any heavenly body which forms the center of a system of orbs. 3. The direct light or warmth of the sun; sunshine. "Lambs that did frisk in the sun." (Shak) 4. That which resembles the sun, as in splendor or importance; any source of light, warmth, or animation. "For the Lord God is a sun and shield." (Ps. Lxxiv. 11) "I will never consent to put out the sun of sovereignity to posterity. <medicine>" (Eikon Basilike) Sun and planet wheels See Sun and planet wheels, above. Under the sun, in the world; on earth. "There is no new thing under the sun." Sun is often used in the formation of compound adjectives of obvious meaning; as, sun-bright, sun-dried, sun-gilt, sunlike, sun-lit, sun-scorched, and the like. Origin: OE. Sunne, sonne, AS. Sunne; akin to OFries. Sunne, D. Zon, OS. & OHG. Sunna, G. Sonne, Icel. Sunna, Goth. Sunna; perh. Fr. Same root as L. Sol. 297. Cf. Solar, South. Source: Websters Dictionary (01 Mar 1998) |
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| sun protection factor | A number on a scale (from 2 upwards) for rating sunscreens. Sunscreens with an spt of 15 or higher provide the best protection from the sun's harmful rays. (12 Dec 1998) |
| sun star | <zoology> See Sun star, under Sun. Source: Websters Dictionary (01 Mar 1998) |
| sun-struck | <medicine> Overcome by, or affected with, sunstroke; as, sun-struck soldiers. Source: Websters Dictionary (01 Mar 1998) |
| sunbird | <ornithology> Any one of numerous species of small brilliantly coloured birds of the family Nectariniidae, native of Africa, Southern Asia, the East Indies, and Australia. In external appearance and habits they somewhat resemble humming birds, but they are true singing birds (Oscines). The sun bittern. Source: Websters Dictionary (01 Mar 1998) |
| sunburn | The burning or discolouration produced on the skin by the heat of the sun; tan. Source: Websters Dictionary (01 Mar 1998) |
| sunder | A separation into parts; a division or severance. In sunder, into parts. "He breaketh the bow, and cutteth the spear in sunder." See: Sunder, and cf. Asunder. Source: Websters Dictionary (01 Mar 1998) |
| sundew | <botany> Any plant of the genus Drosera, low bog plants whose leaves are beset with pediceled glands which secrete a viscid fluid that glitters like dewdrops and attracts and detains insects. After an insect is caught, the glands curve inward like tentacles and the leaf digests it. Synonym: lustwort. Source: Websters Dictionary (01 Mar 1998) |
| sundial | An instrument to show the time of day by means of the shadow of a gnomon, or style, on a plate. <zoology> Sundial shell, any shell of the genus Solarium. See Solarium. Source: Websters Dictionary (01 Mar 1998) |
| sundog | <meteorology> A luminous spot occasionally seen a few degrees from the sun, supposed to be formed by the intersection of two or more halos, or in a manner similar to that of halos. Source: Websters Dictionary (01 Mar 1998) |
| sundowning | The onset or exacerbation of delirium during the evening or night with improvement or disappearance during the day; most often seen in mid and later stages of dementing disorders, such as Alzheimer's disease. (05 Mar 2000) |
| sunfish | <zoology> A very large oceanic plectognath fish (Mola mola, Mola rotunda, or Orthagoriscus mola) having a broad body and a truncated tail. Any one of numerous species of perch-like North American fresh water fishes of the family Centrachidae. They have a broad, compressed body, and strong dorsal spines. Among the common species of the Eastern United States are Lepomis gibbosus (called also bream, pondfish, pumpkin seed, and sunny), the blue sunfish, or dollardee (L. Pallidus), and the long-eared sunfish (L. Auritus). Several of the species are Synonym: pondfish. The moonfish, or bluntnosed shiner. The opah. The basking, or liver, shark. Any large jellyfish. Source: Websters Dictionary (01 Mar 1998) |
| sunflower | Any plant of the genus Helianthus; so called probably from the form and colour of its flower, which is large disk with yellow rays. The commonly cultivated sunflower is Helianthus annuus, a native of America. Source: Websters Dictionary (01 Mar 1998) |
| sunflower cataract | chalcosis lentis |
| sunflower seed oil | Oil from the seeds of Helianthus annuus (family Compositae); the glycerides consist mainly of the mixed triglycerides, each containing one or two linoleic acid radicals; used as a food, and in dietary supplements. (05 Mar 2000) |
| setting sun sign | <clinical sign> Retraction of the upper lid without upgaze so that the iris seems to "set" below the lower lid; suggestive of neurologic damage in the newborn, but usually clears up without sequelae. See: Collier's sign, Epstein's sign. (05 Mar 2000) |
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