borrowed from German, from chrom- chrom- + Latin affīnis "bordering (on), connected (with)" — more at affinity
Note: The term was introduced by the histologist Alfred Kohn (1867-1959, of Jewish heritage, born in Bohemia, Austria-Hungary) in "Ueber die Nebenniere," Prager Medicinische Wochenschrift, 23. Jahrgang, Nr. 17 (April 28, 1898), p. 194/2.