A type is a single piece of lead with the reversed form of a letter raised on one end. Typesetters collect individual types and arrange them in forms, ink the raised end, and press the types onto paper to print sheets.

From the Guide to Literary Terms by Jack Lynch.
Please send comments to Jack Lynch.
Note: This guide is still in the early stages of development.
Three question marks mean I have to write more on the subject. Bear with me.