The Collaborative International Dictionary of English v.0.48:

Wavelet \Wave"let\, n.
   A little wave; a ripple.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wavelet
    n 1: a small wave on the surface of a liquid [syn: ripple,
         rippling, riffle, wavelet]

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

wavelet

    A waveform that is bounded in both frequency
   and duration.  Wavelet tranforms provide an alternative to
   more traditional Fourier transforms used for analysing
   waveforms, e.g. sound.

   The Fourier transform converts a signal into a continuous
   series of sine waves, each of which is of constant frequency
   and amplitude and of infinite duration.  In contrast, most
   real-world signals (such as music or images) have a finite
   duration and abrupt changes in frequency.

   Wavelet transforms convert a signal into a series of wavelets.
   In theory, signals processed by the wavelet transform can be
   stored more efficiently than ones processed by Fourier
   transform.  Wavelets can also be constructed with rough edges,
   to better approximate real-world signals.

   For example, the United States Federal Bureau of Investigation
   found that Fourier transforms proved inefficient for
   approximating the whorls of fingerprints but a wavelet
   transform resulted in crisper reconstructed images.

   SBG Austria (http://mat.sbg.ac.at/~uhl/wav.html).

   ["Ten Lectures on Wavelets", Ingrid Daubechies].

   (1994-11-09)