The Collaborative International Dictionary of English v.0.48:

Quiesce \Qui*esce"\, v. i. [imp. & p. p. Quiesced; p. pr. &
   vb. n. Quiescing.] [L. quiescere, akin to quies rest,
   quiet. See Quiet, a. & n.]
   To be silent, as a letter; to have no sound. --M. Stuart.
   [1913 Webster] Quiescence

WordNet (r) 3.0 (2006):

quiesce
    v 1: become quiet or quieter; "The audience fell silent when the
         speaker entered" [syn: quieten, hush, quiet,
         quiesce, quiet down, pipe down] [ant: louden]

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

quiesce

    To render quiescent, i.e. temporarily inactive or
   disabled.  For example to quiesce a device (such as a digital
   modem).  It is also a system command in MAX TNT software which
   is used to "Temporarily disable a modem or DS0 channel".

   Also used as an adjective, in the expression "quiesce time".

   (2000-03-05)