screen

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A movable device, especially a framed construction such as a room divider or a decorative panel, designed to divide, conceal, or protect.
• noun One that serves to protect, conceal, or divide.
• noun A coarse sieve used for sifting out fine particles, as of sand, gravel, or coal.
• noun A system for preliminary appraisal and selection of personnel as to their suitability for particular jobs.
• noun A window or door insertion of framed wire or plastic mesh used to keep out insects and permit air flow.
• noun A surface or device on which an image, such as a movie, is displayed for viewing.
• noun The medium in which movies are shown.
• noun A body of troops or ships sent in advance of or surrounding a larger body to protect or warn of attack.
• noun Sports A block, set with the body, that impedes the vision or movement of an opponent.
• noun Football A screen pass.
• transitive verb To provide with a screen or screens.
• transitive verb To show or project (a movie, for example) on a screen.
• transitive verb To conceal from view with a screen or something that acts like a screen: synonym: block.
• transitive verb To protect, guard, or shield.
• transitive verb To separate or sift out (fine particles of sand, for example) by means of a sieve or screen.
• transitive verb To sort through and eliminate unwanted examples of (something).
• transitive verb To examine (a job applicant, for example) systematically in order to determine suitability.
• transitive verb To test or evaluate (a student) to determine placement in an educational system or to identify specific learning needs.
• transitive verb To test or examine for the presence of disease or infection.
• transitive verb To subject to genetic screening.
• transitive verb To block the vision or movement of (an opponent) with the body.
• transitive verb To obscure an opponent's view of (a shot) by positioning oneself between the opponent and the shooter.

from The Century Dictionary.

• To shelter or protect from inconvenience, injury, danger, or observation; cover; conceal.
• To sift or riddle by passing through a screen: as, to screen coal.
• Synonyms To defend, hide, mask, cloak, shroud.
• noun A transparent plate having ruled upon its surface lines, parallel or crossed, placed immediately in front of the sensitive plate in the manufacture of a half-tone negative, in order to break up the shadows by diffraction.
• noun A covered framework, partition, or curtain, either movable or fixed, which serves to protect from the heat of the sun or of a fire, from rain, wind, or cold, or from other inconvenience or danger, or to shelter from observation, conceal, shut off the view, or secure privacy: as, a fire-screen; a folding screen; a window-screen, etc.; hence, such a covered framework, curtain, etc., used for some other purpose: as, a screen upon which images may be cast by a magic lantern; in general, any shelter or means of concealment.
• noun Specifically, in architecture:
• noun An ornamental partition of wood, stone, or metal, usually so placed in a church or other building as to shut out an aisle from the choir, a private chapel from a transept, the nave from the choir, the high altar from the east end, an altar-tomb from a public passage, or to fill any similar purpose. See perclose, and cut under organ-screen.
• noun In some medieval and similar halls, a partition extending across the lower end, forming a lobby within the main entrance-doors, and having ofteu a gallery above.
• noun An architecturally decorated wall inclosing a courtyard or the like. Such a feature as the entire facade of a church may be considered as a screen when it does not correspond with the interior structure, as is commonly the case in Italian and frequent in English churches, but is merely a decorative mask for the building behind it. See cut under reredos.
• noun A kind of riddle or sieve.
• noun A large scarf forming a kind of plaid.
• noun A screen supported on cross-rails, feet, or the like, enabling it to stand firmly, and with hinged flaps which when opened increase its width.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To provide with a shelter or means of concealment; to separate or cut off from inconvenience, injury, or danger; to shelter; to protect; to protect by hiding; to conceal.
• transitive verb To pass, as coal, gravel, ashes, etc., through a screen in order to separate the coarse from the fine, or the worthless from the valuable; to sift.
• transitive verb to examine a group of objects methodically, to separate them into groups or to select one or more for some purpose.
• transitive verb To inspect the qualifications of candidates for a job, to select one or more to be hired.
• transitive verb (Biochem., Med.) to test a large number of samples, in order to find those having specific desirable properties.
• noun Anything that separates or cuts off inconvenience, injury, or danger; that which shelters or conceals from view; a shield or protection.
• noun (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.
• noun 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.