Definition of serum in English:

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Pronunciation: /ˈsɪərəm/

noun (plural sera /ˈsɪərə/ or serums)

[mass noun]
1An amber-coloured, protein-rich liquid which separates out when blood coagulates: the researchers examined blood serum obtained from 471 heterosexual men and women [count noun]: sera were stored at −20°C until tested
More example sentences
  • Blood products, sera, sperm, oocytes and embryos are not included.
  • The number of sera from patients whose blood culture grew B. psuedomallei is only 12.
  • Blood samples were then obtained and sera tested for HIV and hepatitis.
2The blood serum of an animal used to provide immunity to a pathogen or toxin by inoculation or as a diagnostic agent: doctors treated the bites of carpet vipers with serum produced from local snakes
More example sentences
  • He was given a cocktail of vaccines within 10 minutes including anti-plague and anthrax serums.
  • You could be making a fortune out of the drugs, serums and surgical hardware, and yet you have to stand on the sidelines and watch as US drug companies make a killing.


Late 17th century: from Latin, literally 'whey'.

Words that rhyme with serum

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