This is the well-known section mark, sometimes used as a general sign for law and/or bureaucracy.

As a biological sign it can mean a typical specimen of a species.

In typography is used to mean section or paragraph. is synonymous in this respect.

It is the fourth in series of the reference marks.

The section sign (§; Unicode U+00A7, HTML entity §) is a typographical character used mainly to refer to a particular section of a document, such as a legal code. It is frequently used along with the pilcrow (¶), or paragraph sign. When duplicated, as §§, it is read as the plural “sections” (§§ 13–21), much as “pp.” (pages) is the plural of “p.” (page). For an effect comparable to the contemporary use of bold type, early scribes would double stroke letters, hence the sign was developed from a double stroked letter S. Another theory supposes it to have developed from the Hebrew letter gimel (ג). Its usage was similar to paragraphos.

It is also used to represent a type specimen in animals.

A section in the United States Code.

Many Maxis games, from SimCity 3000 onwards, including The Sims, The Sims Online, and The Sims2, use this symbol (with an unusually small loop) to represent the unit of currency in the SimNation, the simoleon.

John Cook uses this symbol as a decoration or design element in many of his Sev Wide Web comics.

Polish police use the section sign on a badge indicating specialty in criminal investigation.In Poland (and other West Slavic countries), the section sign is commonly associated with concept of law and justice. It is commonly displayed on covers of legal books, especially those concerning criminal law. The section sign is also shown on badges of the crime investigation specialty of the Polish police.

Similarly, in Danish, Finnish, German and Swedish, the section sign is used nearly exclusively to refer to articles of legal codes, and hence associated likewise with law and legal matters. (In this usage, it is typically read “paragraph” rather than “section”.)

In some online communities, such as the forums on Craigslist, the section sign in the subject of a forum posting indicates that the subject line comprises the entirety of the posting, and the body is empty.

It’s used with numbers normally:

§17 for Section 17.

in mathematics it’s a type of integral: circular one, but i don’t know if i translated the word good; it means you integrate a value around a surface