Definitions for "Copyfitting"
Keywords:  fit, grapics, galleys, typography, copy
Making adjustments to text size, text leading or otherwise editing the text so it fits in a given space.
In typography, the process of estimating the point size and leading in which a particular piece of copy will need to be set to fit in a (usually) predetermined amount of space.
In galleys or page proofs, replacing deleted material with copy that will occupy the same space so as to keep the resetting of lines to a minimum.