noun

a class or division of people or things regarded as having particular shared characteristics.

the various categories of research

class,classification,categorization,group,grouping,bracket,head,heading,list,listing,set,type,sort,kind,variety,species,genre,breed,style,brand,make,model,family,stamp,cast,ilk,kidney,grade,grading,order,rank,status,division,section,department,compartment,pigeonhole