Signature is a sheet of paper printed on both sides that can be folded multiple times to create part of a publication.
Hickey Picker – a hickey or a particle that causes a defect or blank spot in the printing process.  A hickey picker would remove the cause of the defect, such as the particle, or it would surround the defect with ink removing the blank spot.  Offset Press Man
DPI stands for the amount of dots making up a square inch of a file or picture.  If an object is 300 DPI, it is a high resolution document consisting of 300 dots per square inch.  A 72 DPI is the standard for producing an image for the internet.  A DPI file can be manipulated (resized) without losing quality and is essentially a vector file.  Printing, especially high quality printing, requires a high DPI such as 300.
Bleed refers to the color or picture’s orientation to the edge of the paper.  A quarter inch bleed would extend the color of the picture a quarter inch past the edge on each side of the document. The bleed would be taken off after printing.