[on.o.mas.tics] n pl but sing or pl in constr (1930) 1 a: the science or study of the origins and forms of words esp. as used in a specialized field b: the science or study of the origin and forms of proper names of persons or places
2: the system underlying the formation and use of words esp. for proper names or of words used in a specialized field -- on.o.mas.ti.cian n