The source of the word kern is from the French word carne, meaning "projecting angle, quill of a pen". The French term originated from the Latin cardo, cardinis, meaning "hinge". In the days when all type was cast metal, the parts of a typecasting sort that needed to overlap adjacent letters simply hung off the sort slug's edge. Those overhanging metal pieces were called kerns. At that time, the word kerning only referred to manufacturing the sorts with kerns, while adjusting space between letters during compositing was called inter-spacing or letter spacing. Because this method was not well-suited to some pairs of letters, ligatures were supplied for those glyph combinations, such as the French L', or the combinations ff, fi, fl, ffi, ffl, and others. In digital typography, kerning is usually applied to letter pairs as a number by which the default character spacing should be increased or decreased: a positive value for an increase, a negative value for a decrease. The number is expressed in font units, one unit being a certain fraction of an em (one em is the type size currently used). Different fonts may use different units, but common values are 1000 and 2048 units/em. Thus, for 1000 units/em, a kerning value of 15 means an increase in character spacing by 0.015 of the current type size. (The kerning units for a given font are the same as the units used to express the character widths in that font.)

Square capitals were used to write inscriptions, and less often to supplement everyday handwriting as Latin book hand. For everyday writing the Romans used a current cursive hand known as Latin cursive. Notable examples of square capitals used for inscriptions are found on the Roman Pantheon, Trajan's Column, and the Arch of Titus, all in Rome. These Roman capitals are also called majuscules, as a counterpart to minuscule letters such as Merovingian and Carolingian. Before the 4th century CE, square capitals were used to write de luxe copies of the works of authors categorized as "pagan" by Christians, especially those of Virgil; the only three surviving manuscripts using this letter, among them the Vergilius Augusteus, contain works by Virgil. After the 5th century the square capitals fell out of use, except as a display lettering for titles and chapter headings in conjunction with various script hands for body text: for example, uncials. Edward Catich is noted for the fullest development of the thesis that the inscribed Roman square capitals owed their form, including the serifs, wholly to the use of the flat brush, rather than to the exigencies of the chisel or other stone cutting tools. Although not universally accepted, the brushed-origin thesis had been proposed in the nineteenth century. Catich made a complete study and proposed a convincing ductus by which the forms were created, using a flat brush and then chisel.