screen

n. [ OE. scren, OF. escrein, escran, F. écran, of uncertain origin; cf. G. schirm a screen, OHG. scirm, scerm a protection, shield, or G. schragen a trestle, a stack of wood, or G. schranne a railing. ] 1. Anything that separates or cuts off inconvenience, injury, or danger; that which shelters or conceals from view; a shield or protection; as, a fire screen. [ 1913 Webster ]

Your leavy screens throw down. Shak. [ 1913 Webster ]

Some ambitious men seem as screens to princes in matters of danger and envy. Bacon. [ 1913 Webster ]

2. (Arch.) A dwarf wall or partition carried up to a certain height for separation and protection, as in a church, to separate the aisle from the choir, or the like. [ 1913 Webster ]

3. A surface, as that afforded by a curtain, sheet, wall, etc., upon which an image, as a picture, is thrown by a magic lantern, solar microscope, etc. [ 1913 Webster ]

4. A long, coarse riddle or sieve, sometimes a revolving perforated cylinder, used to separate the coarser from the finer parts, as of coal, sand, gravel, and the like. [ 1913 Webster ]

5. (Cricket) An erection of white canvas or wood placed on the boundary opposite a batsman to enable him to see ball better. [ Webster 1913 Suppl. ]

6. a netting, usu. of metal, contained in a frame, used mostly in windows or doors to allow in fresh air while excluding insects. --
Screen door, a door of which half or more is composed of a screen. --
Screen window, a screen inside a frame, fitted for insertion into a window frame. [ PJC ]

7. The surface of an electronic device, as a television set or computer monitor, on which a visible image is formed. The screen is frequently the surface of a cathode-ray tube containing phosphors excited by the electron beam, but other methods for causing an image to appear on the screen are also used, as in flat-panel displays. [ PJC ]

8. The motion-picture industry; motion pictures. “A star of stage and screen.” [ PJC ]

n. the process of examining or testing objects methodically to find those having desirable properties. See screen{ 3 }. In the pharmaceutical industry, pharmaceutical screening involves testing a large number of samples of substances to find those having desirable pharmacological activity; those samples which have the property sought are called active or positive in the screen. The substances tested may be pure compounds with known structure, mixtures of pure compounds, or complex mixtures obtained by extraction from living organisms. There are often additional sets of test performed on active samples, called
counterscreening to eliminate those samples that may also possess undesirable properties. In the case of screening of mixtures from living organisms, a type of counterscreening called dereplication is usually performed, to determine if the active sample contains a known compound which has previously been studied. [ PJC ]