glass

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

• noun Any of a large class of materials with highly variable mechanical and optical properties that solidify from the molten state without crystallization, are typically made by silicates fusing with boric oxide, aluminum oxide, or phosphorus pentoxide, are generally hard, brittle, and transparent or translucent, and are considered to be supercooled liquids rather than true solids.
• noun Something made of glass or other transparent or translucent material, especially.
• noun A drinking vessel.
• noun A mirror.
• noun A barometer.
• noun A window or windowpane.
• noun The series of transparent plastic sheets that are secured vertically above the boards in many ice rinks.
• noun A pair of lenses mounted in a light frame, used to correct faulty vision or protect the eyes.
• noun A binocular or field glass.
• noun A device, such as a monocle or spyglass, containing a lens or lenses and used as an aid to vision.
• noun The quantity contained by a drinking vessel; a glassful.
• noun Objects made of glass; glassware.
• adjective Made or consisting of glass.
• adjective Fitted with panes of glass; glazed.
• intransitive verb To enclose or encase with glass.
• intransitive verb To put into a glass container.
• intransitive verb To provide with glass or glass parts.
• intransitive verb To make glassy; glaze.
• intransitive verb To see reflected, as in a mirror.
• intransitive verb To reflect.
• intransitive verb To scan (a tract of land or forest, for example) with an optical instrument.
• intransitive verb To become glassy.
• intransitive verb To use an optical instrument, as in looking for game.

from The Century Dictionary.

• noun In petrography, glass is the natural product of the rapid cooling of igneous magmas, and in large masses is known as obsidian, pitchstone, and pumice. It may be colorless or of various colors, as white, yellow, orange, red, green, and black. It forms the ground-mass of many volcanic rocks, being sometimes recognizable by the unaided eye, but often only microscopically. Glass base to the name given to it when it forms the matrix for microscopic crystals in the ground-mass of a rock.
• To case in glass; cover with or as if with glass; protect by a covering of glass.
• To make glassy; give a glazed surface to; glaze or polish.
• To reflect, as a mirror or other reflecting surface; show or observe a reflection of.
• noun A substance resulting from the fusion of a combination of silica (rarely boracic acid) with various bases. See vitreous.
• noun A plate, screen, vessel, instrument, etc., made of glass.
• noun A plate or pane of glass inserted in the frame of a window, picture, clock, hotbed, etc., to admit the light or permit a view, while excluding wind, rain, dust, or other interference.
• noun A looking-glass; a mirror. It was formerly fashionable for ladies to carry a looking-glass hanging from the girdle.
• noun A glass vessel filled with running sand for measuring time, called specifically an hour-glass; hence, the time in which a glass is exhausted of its sand; specifically (nautical), the time in which a half-hour glass is emptied of its sand.
• noun A vessel made of glass: as, a jelly-glass; a finger-glass. Especially—
• noun A drinking-vessel made of glass; hence, the quantity which such a vessel holds, and figuratively what one drinks, especially strong drink: as, fond of his glass.
• noun An observing-instrument made of glass, or of which the main or most important part is of glass. A lens; a telescope; a field-glass. A barometer. A thermometer. An eye-glass: usually in the plural eye-glasses or spectacles.
• noun Glass having a lime base instead of a lead base, in this sense including nearly all the ornamental glassware, vessels, etc., of the best periods and styles, Venetian Spanish, and others.
• noun A kind of glass which is quite colorless, hard, difficultly fusible, and less readily acted upon by chemicals than any other kind of glass. Mirrors are often made of it, and it is largely used for the manufacture of chemical apparatus. It is made from ground quartz, purified potash, and lime.
• noun A musical instrument consisting either of glass tubes or glass bowls, graduated in size, which can be played by the friction of the moistened finger. Also called glass harmonica.
• noun Glass made ornamental by the application of a white metallic film to the unexposed side, giving it a silvery luster.
• noun Less properly, same as enameled glass. See glass-painting.
• noun Glass that has been heated and then suddenly cooled, under the process of F. Siemens. When the articles to be made are such as are generally molded, the molten glass is run into suitable molds and squeezed while it is highly heated, the mold cooling it sufficiently without the liquid bath.
• [Attrib. use of the noun. The older adj. is glazen, q. v.] Made of glass; vitreous: as, a glass bottle.—

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

• transitive verb To reflect, as in a mirror; to mirror; -- used reflexively.
• transitive verb rare To case in glass.
• transitive verb To cover or furnish with glass; to glaze.
• transitive verb To smooth or polish anything, as leater, by rubbing it with a glass burnisher.
• noun A hard, brittle, translucent, and commonly transparent substance, white or colored, having a conchoidal fracture, and made by fusing together sand or silica with lime, potash, soda, or lead oxide. It is used for window panes and mirrors, for articles of table and culinary use, for lenses, and various articles of ornament.