a. rare. [For quinary, after L. quinque.] = QUINARY.
1690. Leybourn, Curs. Math., 339. All Squares … are to be marked with Points … over every Binary or second Figure…. Sursolids over every Quinquenary Figure.
1825. T. Thomson, 1st Princ. Chem., I. 37. Nitrous acid is a quinquenary compound, composed of 1 atom sulphur and 3 atoms oxygen.
