Many items that are now considered art glass were originally intended for use. Often that use has ceased to be relevant, but even if not, in the Victorian era and for some decades beyond useful items were often decorated to a such a high degree that we can now appreciate them for their artistic or design merits.

Some art glass retains its original purpose but has come to be appreciated more for its art than for its use. Collectors of antique perfume bottles, for example, tend to display their items empty. As items of packaging, these bottles would originally have been used and thus would not ordinarily have been considered art glass. However, because of fashion trends, then as now, producers supplied goods in beautiful packaging. Lalique's Art Nouveau and Art Deco designs and Joseph Hoffman's Art Deco designs have come to be considered art glass due to their stylish and highly original decorative designs.
A major shift in the definition of what constituted "Art Glass" came with the 1977 publication of the book Glass - Art Nouveau to Art Deco by Victor Arwas. Following the book's publication there was a growing recognition that moulded, mass-produced glass with little or no decoration but high artistic and fabrication quality