From the blog of typographers Hoefler & Frere-Jones:
Like most punctuation, the paragraph mark (or pilcrow) has an exotic history. It's tempting to recognize the symbol as a "P for paragraph," though the resemblance is incidental: in its original form, the mark was an open C crossed by a vertical line or two, a scribal abbreviation for capitulum, the Latin word for "chapter." Because written forms evolve through haste, the strokes through the C gradually came to descend further and further, its overall shape ultimately coming to resemble the modern "reverse P" by the beginning of the Renaissance.
Visit the site to see examples of the firm's pilcrow designs and to be entertained by passages like this one:
In any case, Pilcrow & Capitulum would make a fine name for a pub, and a grand place to host a typographers' wayzgoose. Or perhaps it's a buddy movie about crime-fighting bibliographers: Capitulum wears cable knit sweaters and drinks single malt, and Pilcrow is a ladies' man who drives an Austin Healey. Catch their madcap adventures.
The etymology of pilcrow is uncertain. According to a Wikipedia entry:
The name may be a derivation of paragraph through parcrafte, but this etymology is uncertain. The Oxford English Dictionary suggests that the word originated as pylcraft, a corrupted form of "paragraph" (earliest reference c.1440).
That entry also includes this interesting bit of information:
In Chinese, the traditional paragraph sign is a thin circle about the same size as a Chinese character. This same mark also serves as a “zero” character, as a stylistic variation of the Chinese character for “zero”. As a paragraph sign, this mark only appears in older books. Its current use is generally as a “zero” character.
Hat tip: Swissmiss.
Image: Wikimedia Commons.