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thiomersal Line breaks: thio|mer¦sal
Pronunciation: /ˌθʌɪə(ʊ)ˈməːs(ə)l/

Entry from British & World English dictionary

Definition of thiomersal in English:


[mass noun]
A compound able to inhibit the growth of bacteria and other microorganisms, used as a medical disinfectant and preservative for biological products.
  • Chemical formula: C9H9O2SHgNa
Example sentences
  • This was strengthened a few weeks ago when US researchers suggested a mercury-based preservative, thiomersal used in the vaccine for whooping cough could be linked to the development of the condition.
  • We are told that the mercury-based preservative thiomersal will no longer be used in the whooping cough vaccine ‘as part of a worldwide aim of reducing exposure to the element.’
  • The removal of the mercury-based preservative, thiomersal, comes weeks after researchers in the US suggested that it could be linked to the development of autism.


1950s; from thio- + mer(cury) + sal(icylate).

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