Definitions of art glass can be as complex and contentious as definitions of what constitutes "art" and will inevitably include many refinements and exceptions. On the one hand "art glass" is not quite of the size, uniqueness and scope to be considered as "art" - unlike glass art - but on the other, was designed or has come to be appreciated more for its decorative excellence, artistic merit or design distinctiveness than for any possible or originally intended use.

"Art glass" has been almost exclusively intended to decorate the home and was historically bought by those who could afford to commission individual work. However this last distinction today is becoming moot as glass artists strive to produce works of ever increasing distinction whether commissioned or not.

At its broadest level "art glass" can most easily be defined in opposition to glass for utilitarian purposes where the usability is more important than artistic design: glassware, for dining, drinking, and cooking in the home, and for the catering and hospitality industries, as well as glass packaging, scientific, industrial, and architectural glass are the mundane products against which "art glass" is to be compared and contrasted.

Art is a term that describes a diverse range of human activities and the products of those activities, but is most often understood to refer to painting, film, photography, sculpture, and other visual media. Music, theatre, dance, literature, and interactive media are included in a broader definition of art or the arts. Until the 17th century, art referred to any skill or mastery and was not differentiated from crafts or sciences, but in modern usage the fine arts are distinguished from acquired skills in general.

Many definitions of art have been proposed by philosophers and others who have characterized art in terms of mimesis, expression, communication of emotion, or other values. During the Romantic period, art came to be seen as "a special faculty of the human mind to be classified with religion and science".

The nature of art, and related concepts such as creativity and interpretation, are explored in a branch of philosophy known as aesthetics.

The Encyclopædia Britannica Online defines art as "the use of skill and imagination in the creation of aesthetic objects, environments, or experiences that can be shared with others". By this definition of the word, artistic works have existed for almost as long as humankind: from early pre-historic art to contemporary art; however, some theories restrict the concept to modern Western societies. The first and broadest sense of art is the one that has remained closest to the older Latin meaning, which roughly translates to "skill" or "craft." A few examples where this meaning proves very broad include artifact, artificial, artifice, medical arts, and military arts. However, there are many other colloquial uses of the word, all with some relation to its etymology.

Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle and optically transparent.

The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica (SiO₂) plus Na₂O, CaO, and several minor additives. Often, the term glass is used in a restricted sense to refer to this specific use.

In science, however, the term glass is usually defined in a much wider sense, including every solid that possesses a non-crystalline (i.e., amorphous) structure and that exhibits a glass transition when heated towards the liquid state. In this wider sense, glasses can be made of quite different classes of materials: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass, polycarbonate, polyethylene terephthalate) are a lighter alternative to traditional silica glasses.

Silica (the chemical compound SiO₂) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called fulgurite.

Mark Montano is an American interior designer, artist, writer, and TV personality.

Mark Montano is perhaps best known for three series on the Style Network and The Learning Channel: 10 Years Younger, which he hosted, While You Were Out, on which he frequently appears as a designer, and My Celebrity Home on which he is both host and designer. Montano can currently be seen on WE TV's new show, "She's Moving In". Montano has a flamboyant design sense that homeowners on While You Were Out are sometimes less than enthused about at first, but he usually wins them over with his boisterous personality.

On My Celebrity Home, Mark tours a celebrity's home and gives their style to a fan. Mark is currently filming MY HOME 2.0 which will air on FOX and Fios channels nationwide starting in April 2010.

Mark Montano is the author of several successful books. "The Big-Ass Book of Crafts", published through SimonSpotlight, subsidiary of Simon & Schuster, owned by parent company CBS, was released on February 18, 2008 and is now the number 1 selling craft book in America. The Big-Ass Book of Crafts is currently in its 7th printing as of January 2009. The Big-Ass Book of Home Decor is on shelves starting April, 2010. For further tips from The Big-Ass Book of Home Decor, there is the companion website and his Typepad blog. In January 2011, Pulp Fiction: Perfect Paper Projects, was published and on October 11, The Big-Ass Book of Crafts 2 was officially on bookstore shelves everywhere.

Louis Comfort Tiffany (February 18, 1848 – January 17, 1933) was an American artist and designer who worked in the decorative arts and is best known for his work in stained glass. He is the American artist most associated with the Art Nouveau  and Aesthetic movements. Tiffany was affiliated with a prestigious collaborative of designers known as the Associated Artists, which included Lockwood de Forest, Candace Wheeler, and Samuel Colman. Tiffany designed stained glass windows and lamps, glass mosaics, blown glass, ceramics, jewelery, enamels and metalwork.

Tiffany was the son of Charles Lewis Tiffany, founder of Tiffany and Company; and Harriet Olivia Avery Young. He attended school at Pennsylvania Military Academy in Chester, Pennsylvania, and Eagleswood Military Academy in Perth Amboy, New Jersey. His first artistic training was as a painter, studying under George Inness and Samuel Colman in New York City and Léon Bailly in Paris.

Tiffany started out as a painter, but became interested in glassmaking from about 1875 and worked at several glasshouses in Brooklyn between then and 1878. In 1879, he joined with Candace Wheeler, Samuel Colman and Lockwood de Forest to form Louis Comfort Tiffany and Associated American Artists. Tiffany's leadership and talent, as well as his father's money and connections, led this business to thrive.