Definition of serum
- an antiaging facial serum
The patient was administered serum.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'serum.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use: 1665See Words from the same year
medical : the part of blood that is like water and that contains substances (called antibodies) that fight disease
medical : serum from an animal's blood that can be added to a person's blood to prevent or cure disease
biology : the watery part of a fluid found in a plant
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