Using the Not Equal Sign
The not equal sign is an equals sign with a slash through it, and it makes the negative claim: whatever sits on the left is not the same as whatever sits on the right. In algebra it states a constraint (x ≠ 0 before dividing by x), in set theory it separates distinct elements, and in logic it is the negation of the identity relation. The slash leans the same way as a forward slash, rising from bottom-left to top-right.
Spacing and layout
Like =, the sign takes a space on each side: 2 + 2 ≠ 5. It shares the maths axis with + and = so the bars line up across an equation. Never assemble it from = and / typed together; the result looks like two separate characters and confuses screen readers, which announce the real symbol as "not equal to".
Programming equivalents
Almost no language accepts ≠ in source code. C, Java, JavaScript, Python, Go and Rust write != ; SQL, Excel, Pascal and older BASIC dialects use <> ; APL and some Lisp variants are the rare exceptions that read the Unicode character directly. Many editors and fonts with ligatures, such as Fira Code or JetBrains Mono, draw != as ≠ on screen while keeping the two-character sequence in the file, which is where a lot of people first see the glyph. In comments, documentation and Markdown it is safe to write the real ≠ because nothing has to parse it.
Related relations
≠ is the strongest form of "different". ≈ (the approximately equal sign) says two values are close, ≢ negates the triple-bar identity ≡, and ≟ flags an equality you still need to check. The ordering relations ≤ and ≥ (see the less than or equal sign) each imply "≠ or =", and a strict < already implies ≠.
Typing it
macOS has the easiest route: Option + =. Windows offers no Latin-1 Alt code, so use the emoji panel's Symbols tab or, in Word, type 2260 and press Alt + X. Both the iPhone keyboard and Gboard hide ≠ under a long-press of the = key on the symbols page, which makes it one of the few maths signs you can type on a phone without a text replacement.
In captions and bios
Outside maths the glyph has become a compact rhetorical device: "quiet ≠ shy", "rest ≠ lazy", "expensive ≠ good". It reads as confident and slightly nerdy, and it works in Instagram captions, Twitter display names and Discord statuses because it is plain text, not an emoji, so it never changes appearance between devices. Pair it with the strikethrough fonts generator when you want the whole word crossed out rather than a single sign, or with the infinity symbol for a maths-themed handle.