In glass collecting terms moulded glass is the term given to machine pressed glass, produced in the thousands primarily in the north of England. In terms of hand made glass in the Stourbridge area moulds were used to impart decoration to the surface of the glass or to produce the initial form of a vessel. The iron moulds could be a single beaker shape or a multi section, hinged mould. In either case a gather of glass would be placed into it and the bubble blown to form a parison with the surface imprinted with the design. The parison can then be removed from the mould and the vessel blown and finished in the usual manner.
The beaker shaped, non hinged moulds are known as dip moulds.
All the Stourbridge factories had their own moulded designs, some were very similar to each other. Thomas Webb & Sons registered three different designs. Stevens & Williams did not register any mould designs but still have their own distinctive patterns.