Using the Section Symbol
The section sign points readers to a numbered section of a statute, regulation, contract or book. It grew out of two overlapping letters S, short for the Latin signum sectionis, which is why the glyph looks like an S wound around itself. Lawyers see it every day; everyone else meets it mainly in terms-of-service pages and citations.
How to cite with it
The American Bluebook form is title, code, sign, number: 17 U.S.C. § 107. Put a space on each side of the sign, and when you cite more than one section, double it: §§ 106–107 for a range, §§ 106, 110 for a list. The space after § should be a non-breaking one so the sign never ends up stranded at the end of a line. Never start a sentence with the sign; write "Section 107 provides…" instead. German and Scandinavian law uses the same mark but puts it before the number with a space, as in § 823 BGB, and German readers pronounce it "Paragraph".
Section versus paragraph
The section sign refers to a numbered section; the pilcrow ¶ refers to a numbered paragraph, which is why court filings cite "Compl. ¶ 12" but "42 U.S.C. § 1983". Mixing them up is the most common mistake in student briefs. Contracts usually number clauses rather than paragraphs, so § is the right choice when you cite a clause of an agreement.
As a footnote mark
Before numbered footnotes took over, printers used a fixed sequence of reference marks: asterisk, dagger, double dagger, section sign, then parallel bars and pilcrow. The section sign is therefore the fourth footnote on a page in older books, and some academic journals still follow the sequence for table notes.
Rendering
Because § is part of Latin-1, it renders everywhere, including in game chat, SMS and every phone keyboard font. Windows users type it with Alt + 0167 on the numeric keypad, Mac users with Option + 6, and iPhone users by holding the & key on the number keyboard. Word documents also pick it up from the Insert → Symbol dialog under Latin-1 Supplement.
Outside the law
The sign has a second career as decoration. Its symmetrical shape works as a divider in bios ("writer § editor § cat person"), as a fake-official prefix in Discord names and in the small-caps editorial look that pairs well with a typewriter font. It reads as "legal" or "academic" to most people, which is why law students, paralegals and policy accounts put it in their Instagram and X display names. If you want the matching legal set, the registered symbol and trademark symbol pages cover the marks that appear beside brand names.