The Free On-line Dictionary of Computing (30 December 2018):

fixed-point

    A number representation scheme where a number,
   F is represented by an integer I such that F=I*R^-P, where R is
   the (assumed) radix of the representation and P is the (fixed)
   number of digits after the radix point.

   On computers with no floating-point unit, fixed-point
   calculations are significantly faster than floating-point as
   all the operations are basically integer operations.
   Fixed-point representation also has the advantage of having
   uniform density, i.e., the smallest resolvable difference of
   the representation is R^-P throughout the representable range,
   in contrast to floating-point representations.

   For example, in PL/I, FIXED data has both a precision and
   a scale-factor (P above).  So a number declared as 'FIXED
   DECIMAL(7,2)' has a precision of seven and a scale-factor of
   two, indicating five integer and two fractional decimal
   digits.  The smallest difference between numbers will be 0.01.

   (2006-11-15)