comparator
Com"pa*ra`tor ( or ), n. Etym: [L., a comparater.] (Physics) Defn: An instrument or machine for comparing anything to be measured with a standard measure; -- applied especially to a machine for comparing standards of length.
Com"pa*ra`tor ( or ), n. Etym: [L., a comparater.] (Physics) Defn: An instrument or machine for comparing anything to be measured with a standard measure; -- applied especially to a machine for comparing standards of length.