Quinary system

from The Collaborative International Dictionary of English v.0.48

Quinary \Qui"na*ry\, a. [L. quinarius, from quini five each,
   akin to quinque five: cf. F. quinaire. See {Five}.]
   Consisting of five; arranged by fives. --Boyle.
   [1913 Webster]

   {Quinary system} (Zool.), a fanciful classification based on
      the hypothesis that each group contains five types.
      [1913 Webster]