Glassware formed by placing a blob of molten glass in a metal mold, then pressing it with a metal plunger or "follower" to form the inside shape. The resultant piece, termed "mold-pressed," has an interior form independent of the exterior, in contrast to mold-blown glass, whose interior corresponds to the outer form. The process of pressing glass was first mechanized in the United States between 1820 and 1830.
Source: Glass: A Pocket Dictionary of Terms Commonly Used to Describe Glass and Glassmaking compiled by David Whitehouse of The Corning Museum of Glass.