¶

Before the paragraph became an indent and a blank line, it was a sign painted amid the running text: the pilcrow, a crossed C for capitulum. Manuscripts showed it in red; the printing press retired it.

It survives in hiding: it is the character editors reveal when you switch on “invisible characters”, one per Enter. In references, ¶ 3 addresses the third paragraph. The entity is ¶.

Hidden:   every Enter in the editor records a ¶ nobody sees
Shown:    see § 12, ¶ 2 — the second paragraph of section twelve