In prepress, an alternate term for image assembly or stripping. See Stripping.
In binding and finishing, assembling refers collectively to collating, gathering, or inserting—or, in other words, collecting pages or signatures into complete sets as a prelude to binding. See Binding and Finishing.
In typography, the term assembling referred to collecting and pasting up set type onto a mechanical. In hand-set and hot-metal typography, assembling referred to combining metal type slugs on a galley.