/ Dictionary / Index S serum sickness: Meaning and Definition of Find definitions for: se'rum sick"ness Pronunciation: [key] — Pathol. Pathol. a generalized allergic reaction to a foreign serum or drug, characterized by fever, skin rash, enlarged lymph nodes, and painful joints. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. serum hepatitis serv. Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language