Definitions/serif fonts etc.

Serif: A slight projection finishing off a stroke of a letter in certain typefaces.

Sans-Serif: Without a slight projection finishing off a stroke of a letter in certain typefaces.

Margin: The edge or border of something.

Guide: A person who advises or shows the way to others.

Bleed: The zone outside the trim area.

CMYK: A color model in which all colors are described as a mixture of these four process colors.

Image Resolution: The detail an image holds. 

Proof Copy: A copy of (a book, story, etc) made from trial impressions made from composed type, or print-outs (from a laser printer, etc) for the correction of errors.

Art board: A type of good-quality cardboard used for illustration and painting.

Registration Mark: Marks make to a surface to help with alignment.