In papermaking, an alternate term for sizing. See Sizing.
In ink manufacturing, size is an ink that retains a considerable degree of tack, or stickiness, after it has dried, allowing for the application of metallic powder (or other types of powders) to provide an additional metallic luster to the printing (a process called bronze dusting).
In binding and finishing, size is a mixture (often containing albumen) used in gilding or foil stamping to facilitate the adhesion of the gold leaf to the book cover.