The slash is more correctly called the solidus, the oblique or the virgule. We see it in URLs all the time.
It is much older than the interweb, of course.
If you are old enough, and British enough, you’ll remember it as the mark for a shilling: 2/- meant two shillings in pre-decimal currency. It was also used after the number of pounds: £4/5/3½ is ’four pounds, five shillings, threepence halfpenny’, that last bit pronounced thruppence hayp’ny.
The ½ symbol calls to mind another use of the solidus, in fractions (when the numbers aren’t placed vertically, with a straight line between). It is also used to express per, as in 100km/h. These are essentially the same usage, per here being the Latin for ‘by’ (1 (divided) by 2, 100 km by the hour).
We also use the slash in colloquial abbreviations where it separates the initial letters of syllables: A/C (‘air-conditioning’), b/c (‘because’), w/e (‘week-end’), w/o (‘without’).
So far so good, but there are some problematic uses of the solidus.
I can never remember which is a forward slash and which a backward one. Doesn’t it depend on which way you’re facing?
More significantly, the solidus can mean or but it can also stand for and. This might cause interpretive difficulties.
He/she and s/he probably mean ‘he or she’ and ’she or he’, but perhaps now have an element of gender fluidity to them.
In constructions like and/or, the solidus clearly means or. (But don’t use and/or, for reasons I’ve pointed out previously.)
The solidus can also function as and, as in this piece from the Law Society which describes James Wilson Morrice as ‘probably the most internationally renowned Ontario lawyer/artist’.
Better to say lawyer who was also an artist or lawyer-artist.
Why? Because it could be unclear whether your solidus is disjunctive (or) or conjunctive (and).
The party room and gym in this luxury condominium have state-of-the-art audio/video systems.
Hmm, that probably means they have both audio and video, but you can never be too sure…
Whatever you do, please don’t follow the lead of this writer for Slate, who spelled out each solidus as the word slash:
President Donald Trump issued a stunning threat-slash-promise-slash-constitutional fantasy.
We might do this in speech, but please — not in writing.
Thanks to John Hightower of Lanier Ford Shaver & Payne PC in Huntsville, Alabama, for suggesting the topic and directing me to that Slate horror.