Grammar quiz time! Say the following URL out loud, as if you were giving it out over the phone: www.google.com/analytics.
Did you just say “double-u double-u double-u dot google dot com backslash analytics”? The good news is that you’re not alone; lots of people would say the same thing. The bad news is that you made an error: The punctuation mark / is not a backslash.
When it tilts to the right, / is just called a slash. In British English, it’s called a stroke. In English that nobody except the dictionary uses, it’s called a solidus or a virgule. If you want to clearly distinguish the mark from a backslash, you can call it a forward slash, but you don’t generally need to say the forward part.
The slash has a lot of uses: showing alternatives (he/she), writing fractions (1/3), expressing a two-year span (the 1997/98 fiscal year), writing dates (1/20/2013), abbreviating per (80 miles/hour), expressing a line break in quoted poetry (“Let us go then, you and I, / When the evening is spread out against the sky”), and—of course—to separate the domain from the path in a URL (www.npr.org/blogs/money/).
The backslash was invented for and is only used in programming language, so unless you’re a programmer, you probably won’t run into it very often. It is used for different purposes in different coding languages, but it usually indicates that whatever follows the backslash should be treated differently than what came before it.
The really good news is that this is one of the easiest punctuation rules to memorize: A backslash points backward (\) and a [forward] slash points forward (/). Remember this next time you’re giving out a URL, and you’ll be sure to say it right.