| sigaultian | <surgery> Pertaining to Sigault, a French physician. See Symphyseotomy. Source: Websters Dictionary (01 Mar 1998) |
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| Siggaard-Andersen nomogram | A nomogram used to predict acid-base composition of blood by the slope and position of a buffer line constructed when PCO2 on a logarithmic scale is plotted against pH. (05 Mar 2000) |
| Siggaard-Andersen, Ole | <person> Danish clinical biochemist, *1932. See: Siggaard-Andersen nomogram. (05 Mar 2000) |
| sigh | 1. A deep and prolonged audible inspiration or respiration of air, as when fatigued or grieved; the act of sighing. "I could drive the boat with my sighs." (Shak) 2. Figuratively, a manifestation of grief; a lanent. "With their sighs the air Frequenting, sent from hearts contrite." (Milton) Origin: OE. Sigh; cf. OE. Sik. See Sigh. 1. To exhale (the breath) in sighs. "Never man sighed truer breath." (Shak) 2. To utter sighs over; to lament or mourn over. "Ages to come, and men unborn, Shall bless her name, and sigh her fate." (Pior) 3. To express by sighs; to utter in or with sighs. "They . . . Sighed forth proverbs." (Shak) "The gentle swain . . . Sighs back her grief." (Hoole) Source: Websters Dictionary (01 Mar 1998) |
| sight | 1. The act of seeing; perception of objects by the eye; view; as, to gain sight of land. "A cloud received him out of their sight." (Acts. I. 9) 2. The power of seeing; the faculty of vision, or of perceiving objects by the instrumentality of the eyes. "Thy sight is young, And thou shalt read when mine begin to dazzle." (Shak) "O loss of sight, of thee I most complain!" (Milton) 3. The state of admitting unobstructed vision; visibility; open view; region which the eye at one time surveys; space through which the power of vision extends; as, an object within sight. 4. A spectacle; a view; a show; something worth seeing. "Moses said, I will now turn aside and see this great sight, why the bush is not burnt." (Ex. Iii. 3) "They never saw a sight so fair." (Spenser) 5. The instrument of seeing; the eye. "Why cloud they not their sights?" (Shak) 6. Inspection; examination; as, a letter intended for the sight of only one person. 7. Mental view; opinion; judgment; as, in their sight it was harmless. "That which is highly esteemed among men is abomination in the sight of God." (Luke xvi. 15) 8. A small aperture through which objects are to be seen, and by which their direction is settled or ascertained; as, the sight of a quadrant. "Thier eyes of fire sparking through sights of steel." (Shak) 9. A small piece of metal, fixed or movable, on the breech, muzzle, center, or trunnion of a gun, or on the breech and the muzzle of a rifle, pistol, etc, by means of which the eye is guided in aiming. 10. In a drawing, picture, etc, that part of the surface, as of paper or canvas, which is within the frame or the border or margin. In a frame or the like, the open space, the opening. 11. A great number, quantity, or sum; as, a sight of money. Sight in this last sense was formerly employed in the best usage. "A sight of lawyers." "A wonder sight of flowers." (Gower) at sight, as soon as seen, or presented to sight; as, a draft payable at sight: to read Greek at sight; to shoot a person at sight. Front sight A front sight through which the objects aimed at may be seen, in distinction from one that hides the object. A rear sight having an open notch instead of an aperture. Peep sight, Rear sight. See Peep, and Rear. Sight draft, an order, or bill of exchange, directing the payment of money at sight. To take sight, to take aim; to look for the purpose of directing a piece of artillery, or the like. Synonym: Vision, view, show, spectacle, representation, exhibition. Origin: OE. Sight, sit, siht, AS. Siht, gesiht, gesih, gesieh, gesyh; akin to D. Gezicht, G. Sicht, gesicht, Dan. Sigte, Sw. Sigt, from the root of E. See. See See. Source: Websters Dictionary (01 Mar 1998) |
| sight blindness | A form of aphasia in which the significance of signs and symbols is not appreciated. Synonym: sight blindness. Synonym: asemasia, asaemia. Origin: G. A-priv. + symbolon, an outward sign (05 Mar 2000) |
| sigillaria | <paleontology> A genus of fossil trees principally found in the coal formation; so named from the seallike leaf scars in vertical rows on the surface. Origin: NL, fem sing. Fr. L. Sigillum a seal. Source: Websters Dictionary (01 Mar 1998) |
| sigillarid | <paleontology> One of an extinct family of cryptagamous trees, including the genus Sigillaria and its allies. Source: Websters Dictionary (01 Mar 1998) |
| sigma | The 18th letter of the Greek alphabet, σ. (05 Mar 2000) |
| sigma bond | <chemistry> A bond formed from the overlap of either two s-orbitals or two hybrid orbitals such as sp3 or sp2 orbitals. (09 Jan 1998) |
| sigma effect | The decrease in apparent viscosity that occurs when a suspension, such as blood, is made to flow through a tube of smaller diameter; observed in tubes less than about 0.3 mm in diameter. Synonym: sigma effect. (05 Mar 2000) |
| sigma factor | Initiation factor (86 kD) that binds to E. Coli DNA dependent RNA polymerase and promotes attachment to specific initiation sites on DNA. Following attachment, the sigma factor is released. (18 Nov 1997) |
| sigma peptide | A peptide with one end bonded to a point within the chain, usually by means of the disulfide group of a cystine residue, so that only one end of the peptide is free; so called since the peptide chain has then the rough shape of the Greek letter sigma; e.g., oxytocin. (05 Mar 2000) |
| sigmatism | Synonym: lisping. Origin: G. Sigma, the letter S (05 Mar 2000) |
| sigmodont | <zoology> Any one of a tribe (Sigmodontes) of rodents which includes all the indigenous rats and mice of America. So called from the form of the ridges of enamel on the crowns of the worn molars. Also used adjectively. Origin: Gr. Sigma +, a tooth. Source: Websters Dictionary (01 Mar 1998) |