The symbol ☞ is a punctuation mark, called an index, manicule (from the Latin root manus for ‘hand’ and manicula for ‘little hand’) or fist. Other names for the symbol include printer’s fist, bishop’s fist, digit, mutton-fist, hand, hand director, pointer, and pointing hand.
This welter of competing aliases may stem from the intensely personal nature of the mark. Though the manicule was part of the furniture of the written page for centuries, it was not a mark of punctuation provided by the writer for the edification of the reader but a part of the apparatus of reading itself, a visual breadcrumb inked into the margin by and for one particular reader. A manicule placed to the right of a line may be of vital significance to me, for instance, but utterly unimportant to you; one reader’s manicule is another’s nuisance to be ignored, avoided, or removed. Indeed, some book collectors prefer to “restore” the cluttered margins of annotated books to their original, pristine cleanliness—or barren emptiness, according to your interpretation—and it may simply be that the manicule never warranted an agreed name.
The term “manicule” itself, taken from the Latin maniculum, or “little hand,” is only used of necessity; having granted the symbol a common name, paleographers can finally get on with investigating the many hands pointing the way through the margins of Renaissance life. —The Mysterious Manicule, Keith Houston
(via I Love Typography)