WordNet (r) 3.0 (2006):

fractal
    n 1: (mathematics) a geometric pattern that is repeated at every
         scale and so cannot be represented by classical geometry

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

fractal

    A fractal is a rough or fragmented
   geometric shape that can be subdivided in parts, each of which
   is (at least approximately) a smaller copy of the whole.
   Fractals are generally self-similar (bits look like the whole)
   and independent of scale (they look similar, no matter how
   close you zoom in).

   Many mathematical structures are fractals; e.g. Sierpinski
   triangle, Koch snowflake, Peano curve, Mandelbrot set
   and Lorenz attractor.  Fractals also describe many
   real-world objects that do not have simple geometric shapes,
   such as clouds, mountains, turbulence, and coastlines.

   Benoit Mandelbrot, the discoverer of the Mandelbrot set,
   coined the term "fractal" in 1975 from the Latin fractus or
   "to break".  He defines a fractal as a set for which the
   Hausdorff Besicovich dimension strictly exceeds the
   topological dimension.  However, he is not satisfied with
   this definition as it excludes sets one would consider
   fractals.

   sci.fractals FAQ
   (ftp://src.doc.ic.ac.uk/usenet/usenet-by-group/sci.fractals/).

   See also fractal compression, fractal dimension, Iterated
   Function System.

   Usenet newsgroups: news:sci.fractals,
   news:alt.binaries.pictures.fractals, news:comp.graphics.

   ["The Fractal Geometry of Nature", Benoit Mandelbrot].

   [Are there non-self-similar fractals?]

   (1997-07-02)