Typography Words of the Day: Slashes

Or, to be more precise: Solidus, Virgule, Backslash

Solidus, Virgule, Backslash

When we speak of the ‘slash’, we are speaking in the vernacular. Properly speaking, in typography, there’s no such thing as one.

Consider the gallery above. From the right: the virgule, the solidus, and the backslash. The first two are common to typography; the last one sees often if using a computer. The differences between the first two are simple, and between the last one and the rest obvious. Each one has a particular use.

The Solidus

The one that’s most close to a 45º angle from the verticle is the solidus. Its a fraction bar; with a superior and inferior digit it is used to construct fractions on a line that look more like fractions and not like two digits and a slanted mark strung together.

The solidus in actionThe solidus in action.

It comes to us from from the Roman Empire via England. The solidus was originally a Roman coin, introduced in AD 309; there were 72 of these to the libra, or the Roman pound. The British based their currency system on the Roman, and through the middle of the 20th Century British currency was composed of pounds, shillings, and pence, written £/s/d; the slashes separating the amounds became known as the solidus.

Since decimalization of the British currency system, the solidus is now best used to express fractions in type.

The Virgule

The virgule is a gift of the Medieval scribe. It is believed that it was first used to indicate a pause in text, and thus could be an ancestor to the comma.

The virgule in actionThe virgule in action.

Latterly, the virgule serves a variety of uses. Not only does the mark form the fraction bar when all glyphs in a fraction share the baseline (known as a level fraction) but it serves a separator in certain contexts, such as between files and folders in a Unix filesystem path, or between lines of verse when typeset as prose.

The Backslash

The backslash is a johnny-come-lately to the family, a gift of the modern computer. Most commonly it can be seen as a separator character in a Microsoft Windows command line file path. For example, A document in a Window’s user’s home account might be:

C:\Documents and Settings\Me\My Documents\Report1.doc

There is currently understood to be no real typographical usage of the backslash other than what technology calls for.

Using Them, and OpenType

The use of the marks should be obvious from their descirptions. Most appropriately, one should not use a solidus where a virgule is called for, and vice versa. A solidus-based fraction in type looks more readable; at smaller sizes, a level fraction may be more readable.

Formerly, a solidus-based fraction had to be cobbled together from the solidus and the numbers involved; only common fractions such as ¼, ½, and ¾ were included in standard sets. The advent of OpenType, with its sophisticated feature set, has made things much easier on the digital typographer; in Adobe InDesign, as an example, all that is necessary is to set the numbers and mark (either solidus or virgule) in a string, highlight the string, and selected “Fraction” from the OpenType item on the Character palette flyout menu, and the string will be converted to a solidus-based fraction automatically.

Reference: The Elements of Typographic Style, version 2.5, Robert Bringhurst

5 thoughts on “Typography Words of the Day: Slashes”

  1. it’s interesting that you posit the virgule as being perhaps an ancestor to the comma because ‘virgule’ means comma in French.

  2. Thank you for that follow-up, and actually, I meant to try to track down the roots of virgule. My research suggested that the virgule desceded from a medieval pause but I couldn’t quite find where the word actually came from.

    Thanks again…this is great!

  3. My recollection (I was not quite 20 when they vanished) is that £sd were generally typographically laid out as £2 10/6 (with a space – not a solidus following the £amount – and here / represents a solidus, at around 45 degrees from vertical, and laid out as a diagonal between the s and d only… and, interestingly, the size of the £xxx was at least the same (and frequently bigger than) the overall height of the s/d rectangle and the s and d numbers were about 55% of the £l (printed labels) and closer to 2/3 in writing, and always placed in the upper right-hand quarter of the label.

    Another point to ponder, where did that diagonal angle come from? The Germans kept the solidus as s and past of “esset” until after WW2, and theirs were both almost vertical… Might an Anglo-Saxon need for a monetary typographical convention have influenced this curiosity?

    BTW, asafoetida might be right, as I believe punctuation first arose in the transcription of – latin – hymns (and poëtry) in the dark middle ages, to permit the compact expression of underlay… and economising the very costly vellum that they used for long-term conservation of the written word. The Romans and Greeks had little use for punctuation, at least in Classical times, and generally used spaces and expected their readers to decode thze many contractions they used instead!

  4. As I recall, the solidus was used between shillings and pence only when they appeared without pounds. For amounts written with all three units, a hyphen was used as a separator, or letters were used, thus:

    £2 10s 6d, or £2-10-6, or 50/6

    Of course, this did not stop individuals from using other formats, such as:

    2/10/6, or (as George writes) £2 10/6

    No pennies was often shown as a hyphen after the solidus:


    often with the solidus shortened and raised, which is not reproducible here.

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