The Collaborative International Dictionary
Frisket
Frisket \Fris"ket\, n. [F. frisguette. Perhaps so named from the velocity or frequency of its motion. See Frisk a.] (Print.) The light frame which holds the sheet of paper to the tympan in printing.
Wiktionary
frisket
n. A thin frame in a printing press that holds the sheet of paper in position and acts as a mask.
Wikipedia
Frisket
A frisket is any material that protects areas of a work from unintended change.