Is it ensure, insure, or assure?
Old English glæs "glass, a glass vessel," from West Germanic *glasam (cf. Old Saxon glas, Middle Dutch and Dutch glas, German Glas, Old Norse gler "glass, looking glass," Danish glar), from PIE *ghel- "to shine, glitter" (cf. Latin glaber "smooth, bald," Old Church Slavonic gladuku, Lithuanian glodus "smooth"), with derivatives referring to colors and bright materials, a word that is the root of widespread words for gray, blue, green, and yellow (cf. Old English glær "amber," Latin glaesum "amber," Old Irish glass "green, blue, gray," Welsh glas "blue;" see Chloe). Sense of "drinking glass" is early 13c.
The glass slipper in "Cinderella" is perhaps an error by Charles Perrault, translating in 1697, mistaking Old French voir "ermine, fur" for verre "glass." In other versions of the tale it is a fur slipper. The proverb about people in glass houses throwing stones is attested by 1779, but earlier forms go back to 17c.:
Who hath glass-windows of his own must take heed how he throws stones at his house. ... He that hath a body made of glass must not throw stones at another. [John Ray, "Handbook of Proverbs," 1670]
late 14c., "to fit with glass;" 1570s, "to cover with glass," from glass (n.). Related: Glassed; glassing.
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.
Something usually made of glass, such as a window, mirror, drinking vessel.
glasses A pair of lenses mounted in a light frame, used to correct faulty vision or protect the eyes. Also called spectacles.
A device, such as a monocle or spyglass, containing a lens or lenses and used as an aid to vision.
A usually transparent or translucent material that has no crystalline structure yet behaves like a solid. Common glass is generally composed of a silicate (such as silicon oxide, or quartz) combined with an alkali and sometimes other substances. The glass used in windows and windshields, called soda glass, is made by melting a silicate with sodium carbonate (soda) and calcium oxide (lime). Other types of glass are made by adding other chemical compounds. Adding boron oxide causes some silicon atoms to be replaced by boron atoms, resulting in a tougher glass that remains solid at high temperatures, used for cooking utensils and scientific apparatuses. Glass used for decorative purposes often has iron in it to alter its optical properties.
Our Living Language : Common sand and glass are both made primarily of silicon and oxygen, yet sand is opaque and glass is transparent. Glass owes its transparency partly to the fact that it is not a typical solid. On the molecular level, solids usually have a highly regular, three-dimensional crystalline structure; the regularities distributed throughout the solid act as mirrors that scatter incoming light. Glass, however, consists of molecules which, though relatively motionless like a typical solid, are not arranged in regular patterns and thus exhibit little scattering; light passes directly through. At a specific temperature, called the melting point, the intermolecular forces holding together the components of a typical solid can no longer maintain the regular structure, which then breaks down, and the material undergoes a phase transition from solid to liquid. The phase transition in glass, however, depends on how quickly the glass is heated (or how quickly it cools), due to its irregular solid structure.
was known to the Egyptians at a very early period of their national history, at least B.C. 1500. Various articles both useful and ornamental were made of it, as bottles, vases, etc. A glass bottle with the name of Sargon on it was found among the ruins of the north-west palace of Nimroud. The Hebrew word _zekukith_ (Job 28:17), rendered in the Authorized Version "crystal," is rightly rendered in the Revised Version "glass." This is the only allusion to glass found in the Old Testament. It is referred to in the New Testament in Rev. 4:6; 15:2; 21:18, 21. In Job 37:18, the word rendered "looking-glass" is in the Revised Version properly rendered "mirror," formed, i.e., of some metal. (Comp. Ex. 38:8: "looking-glasses" are brazen mirrors, R.V.). A mirror is referred to also in James 1:23.