From sub- + octuple. <span class="searchmatch">suboctuple</span> (not comparable) (obsolete) Containing one part of eight; in the ratio of one to eight. 1648, John Wilkins, Mathematical...
be in a subduple proportion; so two of them abate half of that which remains, and cause a subquadruple proportion, three a sextuple, four a <span class="searchmatch">suboctuple</span>....
so two of them abate half of that which remains, and cause a subquadruple proportion, three a sextuple, four a <span class="searchmatch">suboctuple</span>. indicating one part of two...