a process of printing that transfers the image from a letterpress-type relief plate to a roller or blanket from which it is offset.
Origin of letterset
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a method of rotary printing in which ink is transferred from raised surfaces to paper via a rubber-covered cylinder
Word Origin for letterset
C20: from letter (press) + (off) set
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012