An asterisk (*) is a typographical symbol or glyph. It is so called because it resembles a star, (Latin astra). Typographers call it a splat (This may derive from the "squashed-bug" appearance of the asterisk on many early line printers). Computer scientists often pronounce it as star (as, for example, in the A* algorithm).

Uses of the asterisk include:

  • In written text, the asterisk is used to call out a footnote or otherwise mark something.
  • In linguistics, an asterisk next to a word may represent a nonstandard usage or a historically reconstructed word.
  • In computing, the asterisk is sometimes used as a wildcard, meaning that it stands for one or more unspecified characters.
  • Many programming languages and calculators use the asterisk as a symbol for multiplication.
  • In Unix and Perl, the asterisk is often used as a Kleene star, which means it stands for zero or more copies of the preceding regular expression.
  • On a Touch-Tone telephone keypad, * (called star) is one of the two special keys, and is found on the left of the zero. (The other is the number sign (or pound or hash) key.)

In computer programming, the asterisk corresponds to Unicode and ASCII character 42, or 0x002A.
Not to be confused with Asterix, the character of children's comic books.