class-

(Latin: division according to rank; class, division, army, fleet)

subclass
superclass
unclassifiable (adjective) (not comparable)
Not disposed to be assigned to a certain category; unidentifiable: Mrs. Green's style of writing was unclassifiable being partly romantic, partly historical, partly crime, and all that mixed up in one book.
unclassified
underclass
underclassman
upperclassman