Glass is typically either blown or pressed into a mold. (although there are other techniques). Patterned glass has a unique pattern to its mold making it patterned pressed glass. There is also pressed glass that is cut in addition making it a combination of cut and pressed glass. Blown glass can be etched for design. This isn't the story in it's entirety but will get you started in understanding the different terms. There are a lot of good books out there that explain the history and will give you a better understanding of how it all came about. You will see the patterned and pressed terms interchanged but I think patterned glass refers mostly to the earlier makers of pressed glass, flint (lead) or non flint when the pattern was very detailed and distinguishable. For example the acronym EAPG stands for Early American Pattern Glass which was made from molds that the glass mixture was poured into and pressed together to make a piece of glassware. Okay I'll stop talking before I start to confuse myself. Anyone feel free to correct anything I might have misstated.