Noun

Singular glass

Plural countable and uncountable; plural glasses

glass (countable and uncountable; plural glasses)

1. (uncountable) A solid, transparent substance made by melting sand with a mixture of soda, potash and lime.

   The tabletop is made of glass.

2. A vessel from which one drinks, especially one made of glass, plastic, or similar translucent or semi-translucent material.

   Fill my glass with milk please.

3. The quantity of liquid contained in such a vessel.

   Would you like a glass of milk?

4. (physics, uncountable) Amorphous (non-crystalline) substance.

   A popular myth is that window glass actually is an extremely viscous liquid.

5. (uncountable) Glassware.

   We collected art glass.

6. A mirror.

   She adjusted her lipstick in the glass.

7. A magnifying glass or telescope.
8. (basketball, colloquial) The backboard.

   He caught the rebound off of the glass.

9. (ice hockey) The clear, protective screen surrounding a hockey rink.

   He fired the outlet pass off the glass.

Derived terms

• carnival glass
• cheval glass
• eyeglasses
• glassblower
• glassblowing
• glasses

• glassformer
• glass frog
• glasshouse
• glassless
• glassmaker
• glassware

• glasswork
• glassy
• isinglass
• looking glass
• magnifying glass
• spyglass

Glass generally refers to hard, brittle, transparent material, such as those used for windows, many bottles, or eyewear. Examples of such materials include, but are not limited to, soda-lime glass, borosilicate glass, acrylic glass, sugar glass, isinglass (Muscovy-glass), or aluminium oxynitride. In the technical sense, glass is an inorganic product of fusion which has been cooled through the glass transition to a rigid condition without crystallizing. Many glasses contain silica as their main component and glass former.

In the scientific sense the term glass is often extended to all amorphous solids (and melts that easily form amorphous solids), including plastics, resins, or other silica-free amorphous solids. In addition, besides traditional melting techniques, any other means of preparation are considered, such as ion implantation, and the sol-gel method. However, and physics commonly includes only inorganic amorphous solids, while plastics and similar organics are covered by polymer science, biology and further scientific disciplines.

Glass plays an essential role in science and industry. The optical and physical properties of glass make it suitable for applications such as flat glass, container glass, optics and optoelectronics material, laboratory equipment, thermal insulator (glass wool), reinforcement fiber (glass-reinforced plastic, glass fiber reinforced concrete), and art.

The term glass developed in the late Roman Empire. It was in the Roman glassmaking center at Trier, Germany, that the late-Latin term glesum originated, probably from a Germanic word for a transparent, lustrous substance.