Tighten \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.