parallel
A character consisting of two parallel vertical lines, used in the text to direct attention to a similarly marked note in the margin or at the foot of a page.
parallel: the double-line footnote marker in print
A parallel, or double dagger, is a typographical symbol consisting of two short vertical lines placed side by side, and used to mark a passage in running text that corresponds to an annotation elsewhere on the page or in endnotes. It appears as ‖ and serves as a reference call, directing the reader's eye to matching text in the margin, footer, or notes section.
In a marked hierarchy of footnote symbols, the parallel occupies a specific rung. The standard ascending sequence runs: asterisk (*), dagger (†), double dagger (‡), section sign (§), and then parallel (‖). Some typographers continue with pilcrow (¶) and other marks. This ordering allows a single page to carry multiple distinct notes without repetition, each callout matching its own annotation by symbol rather than by number.
Parallels are most common in academic texts, critical editions, and legal documents where numerical footnotes would conflict with page numbers or internal numbering schemes, or where the visual distinction of symbolic markers is preferred. They are also used when a document must carry both substantive footnotes and reference citations simultaneously, requiring multiple independent note streams. The parallel is less frequent than the dagger but more common than rarer marks in contemporary print.
Setting parallels requires accurate character selection in digital typography. In Unicode, the parallel sign is U+2016 (double vertical line); it should not be confused with the doubled pipe symbol (||) used in programming or the broken bar (¦). Typefaces vary in the weight and spacing of the parallel glyph, and poor rendering can make it visually unclear or too thin to print reliably at small point sizes.
The name derives from the visual appearance: two lines running alongside one another without meeting, just as the marked text and its note run in parallel through the document. Older printing traditions sometimes used ornamental variants or hand-drawn parallels, but modern typesetting has standardized the form across families and sizes.