The asterisk 
,
also called a "star," is used for a number of
different purposed in mathematics. The most common usage is to denote multiplication
so, for example, 
.
When used as a superscript, the asterisk is commonly voiced "
-star." A raised asterisk is used to denote the adjoint 
, or sometimes the complex
conjugate.
A doubled asterisk 
is used in the Wolfram Language to
denote noncommutative multiplication.
However, in FORTRAN, a doubled asterisk denotes exponentiation (Calderbank
1989, p. 29).
