In metal typesetting, a font is a particular size, weight and style of a typeface. Each font was a set of type, one piece for each glyph. In modern usage, with the advent of digital typography, font is frequently synonymous with typeface, in particular, the use of vector or outline fonts means that different sizes of a typeface can be dynamically generated from one design. The word font derives from Middle French fonte melted, a casting, the term refers to the process of casting metal type at a type foundry. In a manual printing house the word font would refer to a set of metal type that would be used to typeset an entire page. Unlike a digital typeface it would not include a definition of each character. A font when bought new would often be sold as 12pt 14A 34a, meaning that it would be a size 12-point font containing 14 uppercase As, given the name upper and lowercase because of which case the metal type was located in, otherwise known as majuscule and minuscule. The rest of the characters would be provided in quantities appropriate for the distribution of letters in that language. Some metal type characters required in typesetting, such as dashes, spaces and line-height spacers, were not part of a specific font, line spacing is still often called leading, because the strips used for line spacing were made of lead. In the 1880s–90s, hot lead typesetting was invented, in which type was cast as it was set, either piece by piece or in entire lines of type at one time. In European alphabetic scripts, i. e. Latin, Cyrillic and Greek, the main properties are the stroke width, called weight, the style or angle. The regular or standard font is sometimes labeled roman, both to distinguish it from bold or thin and from italic or oblique. The keyword for the default, regular case is often omitted for variants and never repeated, otherwise it would be Bulmer regular italic, Bulmer bold regular, Roman can also refer to the language coverage of a font, acting as a shorthand for Western European. Different fonts of the same typeface may be used in the work for various degrees of readability and emphasis. The weight of a font is the thickness of the character outlines relative to their height. A typeface may come in fonts of many weights, from ultra-light to extra-bold or black, four to six weights are not unusual, many typefaces for office, web and non-professional use come with just a normal and a bold weight which are linked together. If no bold weight is provided, many renderers support faking a bolder font by rendering the outline a second time at an offset, the base weight differs among typefaces, that means one normal font may appear bolder than some other normal font. For example, fonts intended to be used in posters are often quite bold by default while fonts for long runs of text are rather light, therefore, weight designations in font names may differ in regard to the actual absolute stroke weight or density of glyphs in the font
A set of optical sizes developed at URW++. The fonts become thicker and more widely spaced as the point size for which they are designed decreases.
Regular and bold versions of three common fonts. Helvetica has a quite monoline design and all strokes increase in weight; less monoline fonts like Optima and Utopia increase the weight of the thicker strokes more and thinner strokes less in bold. In all three designs, the curve on 'n' thins as it joins the left-hand vertical.