Glossary of Terms

Files
Bleeds: Your file will print all the way to the edge of the paper.
Margins: The area surrounding an image that extends from the image to the edge of the page.  
Composition:  Making changes to an existing file, or creating a new file per client instructions.
Pre-flight:  Using a checklist to verify that all components of a file are present and correct.  

Color
CMYK: Abbreviation for cyan, magenta, yellow and black.  The four colors of inks that are used to do full color printing.  
PMS:  A system used to specify spot colors.  Each color has its own Pantone number by which it can be identified.  
RGB:  The RGB color mode is not recommended for print files.  RGB is a subtractive color mode using red, green, and blue light.  Files that are submitted in RGB will be converted to CMYK.    

Proofing
Printed Proof: A digitally printed sample submitted for client approval before the job prints.  It may not be on the actual stock the job will print on, nor be color accurate.  
E-mail Proof:  A pdf of the file is e-mailed to the client for approval before the job prints.  

Paper
Coating:  A clear film applied to paper to make it glossy.
Weight:  The thickness of a paper stock.  It is determined by the weight in pounds of a ream (500) sheets of paper cut to its parent sheet size.    

Types of Printing
Digital Printing:  A term that describes printing presses that create the image from digital data.  
Offset Printing:  An indirect printing method in which the inked image on a press plate is first transferred to a rubber blanket, that in turn “offsets” the inked impression to a press sheet.  

Types of Bindery
Die Cut: A pattern of sharp knives used to stamp specific shapes into paper.  
Foil: A thin decorative metal used in foil stamping.  
Perforate:  The process of punching a row of small holes into a sheet of paper to allow part of it to easily be detached.  
Scoring:  A finishing operation that involves impressing a hard metal rule into the paper surface where a fold is to be made.  This allows the paper to fold easily without any cracking.   
Perfect Binding: A method of book binding.  The book pages are roughened at the spine, glue is applied, and a cover is affixed.   
Saddle Stitch:  Binding booklets with staples on the spine.  

Mailing
NCOA Update:  Your address list is run through US Post Office software and any addresses that have been updated in the last year will be updated on your list to the current address.
Automation:  The lowest postage rates available from the US Post Office are available as incentives for mail that is barcoded, automated, and machinable.
Letter: A mailing piece that qualifies for the lowest postage rate, and doesn't have any dimensions big enough to quality it as a flat.  
Flat:  A mailing piece that is more than 11.5” long, or more than 6.125” high, or more than .25” thick.  

Source:
Glossary of Graphic Communications Fourth Edition, from the Printing Industries of America Press.