× vs ✕ vs ∗ — the multiplication marks

Two of these three are named for multiplication and exactly one of them is an arithmetic operator. The odd one out does not multiply anything, has never multiplied anything, and is formally called MULTIPLICATION X because Unicode inherited the name from a font vendor's catalogue rather than assigning the character a job.

The multiplication sign is the one with a birthday. William Oughtred used the cross for multiplication in Clavis Mathematicae in 1631, and from there it spread into teaching. Leibniz objected almost immediately — too easily mistaken for the letter x — and preferred a raised dot, which is why higher mathematics writes a · b and, more often, writes nothing at all, since ab already means the same thing. The cross survives where clarity for beginners matters more than elegance, and in the place most people actually need it: dimensions. 4 × 6, 1920 × 1080, a 3 × 3 grid. Typing a lowercase x there is the small slip the real character quietly fixes.

Multiplication x comes out of Unicode's Dingbats block, which exists to round-trip one decorative typeface, ITC Zapf Dingbats, so the names in it describe shapes a designer drew rather than roles the standard is handing out. Nobody multiplies with it. What it does all day is close things: the dismiss button on a dialog, the remove control on a filter chip, the clear button at the end of a search field. Knowing its codepoint rather than grabbing whichever X looks right is worth the small effort, because the characters either side of it misbehave in ways that only show up on someone else's device — a heavier weight that fights body text, and an emoji that arrives pre-coloured at icon size and refuses to inherit anything.

The asterisk operator is separated from the keyboard asterisk by height alone, and the height is the entire meaning. An asterisk sits raised, up where a footnote reference belongs. This one is centred on the same axis as a plus or a minus, because in a formula it is an operator between two operands rather than a pointer to a note at the bottom of the page. What it operates on is deliberately left open: it is the generic binary operation of abstract algebra, convolution in signal processing, conjugation in complex analysis. The shape says an operation happens here, and the surrounding text says which one.

The two characters people actually type are not on this list, and both are fine where they belong. The ASCII asterisk is what every programming language means by multiplication, and it is the only one of these a parser will accept — paste ∗ or × into source and you get a syntax error with nothing visible to explain it, because most fonts draw the lookalikes close enough that you will scan past the difference repeatedly. The letter x is the same story in reverse: entirely readable in a handwritten note or a chat message, and a small typographic tell in anything set with care.

So the division of labour is cleaner than the names suggest. × for arithmetic and dimensions a person reads. ✕ for a control a person clicks. ∗ for notation, and only where the operation is deliberately unnamed. ASCII * for anything a machine parses. The multiplication sign has the shortcuts to match how often it is wanted — Alt+0215 on Windows, × in HTML — and the other two have none worth memorising, which is a fair measure of how rarely you should be reaching for them.