system; lineage; ancestry; group (e.g. of colors) (colours); family (e.g. of languages); close (evolutionary) relationship
two reams (of paper); 1000 sheets (of paper); stanza; verse; tribe (in taxonomy); forecast (bet); bet which predicts the top 2 finishers (i.e. quinella or perfecta bet)
system; lineage; corollary; system (range of strata that correspond to a particular time period); (taxonomical) series