Obs. [For visorium (so in F.), aphetic for divisorium (so in G.), a special use of med.L. divisorium a dividing thing or part.] A device formerly used by compositors while setting up, to indicate the line on the copy.
1659. C. Hoole, trans. Comenius’ Vis. World (1672), 190. The Compositor … (according to the Copy, which he hath fastened before him in a Visorum) composeth words in a composing-stick.
1683. Moxon, Mech. Exerc., Printing, xxii. ¶ 4. 212. Some Compositers use Visorums,… pricking the point of the Visorum … upon the Border or Frame of the Case.
1770. Luckombe, Hist. Printing, 383. When our Copy is very wide we use a Divisorium (commonly called Visorum), we chuse to move it each time downwards, to compose what by that means appears from under the Visorum.
