Asterisk is a sign used in Grammar and in Printing. This sign usually takes the form of a star which is put above or next to a word to indicate to the reader that he is being directed to a similar sign where he will find some [relevant] remark or explanation. A string of little stars indicates that several words are missing. The word asterisk was used in the same sense by the ancients; it is a diminutive of ἀστὴρ, star . Isodore [of Seville] mentions it in the first book of his Origenes : Stella enim ἀστὴρ, græco sermone dicitur, à quo asteriscus , stellula, est derivatus . [1] A few lines later he adds that Aristarchus used an asterisk plus a little line *- [that is, an asterisk plus an obelus ] to mark verses of Homer displaced by the copyists: Asteriscus cum obelo ; hâc propriè Aristarchus utebatur in iis versibus qui non suo loco positi erant .  [2] Isodore ibid .

Sometimes an asterisk is used to draw attention to a word or a remark; but it is more usual to use for this purpose the letters NB meaning nota bene , note well.

* The asterisk is a piece of type found in the general collection of a type face. Its printing surface has the shape described above. [3]

Notes

1. “For a star is called ἀστὴρ in Greek, from which astericus, a little star, is derived.”

2. “Asterisk with obelus; Aristarchus used it correctly in those verses which were not positioned in the correct place.” The reference is to Aristarchus of Samothrace (c. 220-c. 143 BC), who produced a critical edition of Homeric texts in the second century BC. See The Oxford Classical Dictionary DOI: 10.1093/acref/9780198606413.001.0001 Aristarchus (2)

3. Throughout the Encyclopédie , when Diderot adds something to an article by someone else, he marks it with an asterisk, as he does here. But here it serves the additional purpose of illustrating the asterisk.