tightening
 緊固; 緊密
 Tight·en v. t. [imp. & p. p. Tightened p. pr. & vb. n. Tightening.] To draw tighter; to straiten; to make more close in any manner.
 Just where I please, with tightened rein
 I'll urge thee round the dusty plain.   --Fawkes.
 Tightening pulley Mach., a pulley which rests, or is forced, against a driving belt to tighten it.
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 tightening
      n : the act of making something tighter; "the tightening of
          economic controls" [ant: loosening]