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vaccine

n. · v.
US //ˌvækˈsin// UK //væksˈiːn// vac·cine
  1. 1 medical treatment (n.)
    B1 Intermediate Medicine

    a substance given to you, usually by a needle, to prevent a specific disease.

    a substance used to stimulate the production of antibodies and provide immunity against one or several diseases. Countable when referring to types or doses; uncountable as a general concept.

    Example

    The doctor gave the child a vaccine to protect her against the flu.

    Example

    Public health officials emphasized that widespread distribution of the vaccine was the most effective strategy for achieving herd immunity within the urban population.
  2. 2 computing (n.)
    C1 Advanced Technical Computing

    a computer program that finds and removes viruses or malware.

    a software utility designed to detect, neutralize, or provide protection against computer viruses and other malicious code.

    Example

    You should install a digital vaccine to keep your laptop safe from hackers.

    Example

    The security suite includes a heuristic vaccine that identifies suspicious file behaviour even if the specific malware signature is not yet in the database.
  3. 3 to give a vaccine (v.)
    C2 Proficiency Archaic Medicine

    to give someone a vaccine to protect them from a disease.

    to treat a person or animal with a vaccine to produce immunity. This verbal use is largely superseded by 'vaccinate' in modern standard English.

    Example

    In the old book, the doctor sought to vaccine the villagers against the pox.

    Example

    Historical records indicate that the physician attempted to vaccine the entire regiment before they embarked for the tropical colonies.

    Usage

    Takes a direct object; usually replaced by 'vaccinate' in contemporary prose.

    Teacher's tip

    Modern speakers almost exclusively use 'vaccinate' as the verb. This form is likely to be encountered only in 19th-century texts.
Etymology 1

The word slips into English in 1799 under the signature of Edward Jenner (1749–1823), who had noticed that milkmaids who caught the mild cowpox sore never seemed to develop the disfiguring smallpox that ravaged the rest of the neighbourhood. Jenner took the Latin adjective vaccīnus, “of or or derived from a cow” (vacca, “cow” + -īnus), stretched it into New Latin variolae vaccīnae, “cow-pustules”, and injected the pus into a small boy who obligingly failed to die of either complaint.

The Royal Society called the paper boldly speculative; the public simply borrowed the first half of the phrase, and vaccine became the shorthand for any preparation that persuades the immune system to rehearse its lines without first taking the stage.

Etymology 2

The noun is part-formed from Latin vaccīnus, ‘of or from cows’, and part-borrowed from French vaccine, a shortening of variole vaccine, ‘cowpox’. The French had already turned the Latin adjective into both noun and adjective: vaccin for the cowpox material itself, vaccine for the disease and the inoculation against it.

The English verb follows obediently from the noun, as verbs usually do once the object is sufficiently in the room. Cognates across the Romance languages follow the same Latin cow: Italian vaccina, Portuguese vacina, Spanish vacuna — all still herd-words, though the cows themselves long ago wandered out of the conversation.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Related words

Last updated June 19, 2026