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See also: înjection


An injection (relation on sets in mathematics)


Borrowed from Middle French injection, from Latin iniectio. The mathematical sense is from French injection, introduced by Nicolas Bourbaki in their treatise Éléments de mathématique.


  • IPA(key): /ɪn.ˈd͡ʒɛk.ʃən/
  • (file)
  • Hyphenation: in‧jec‧tion
  • Rhymes: -ɛkʃən


injection (countable and uncountable, plural injections)

  1. The act of injecting, or something that is injected.
  2. A specimen prepared by injection.
  3. (category theory) A morphism from either one of the two components of a coproduct to that coproduct.
  4. (construction) The act of inserting materials like concrete grout or gravel by using high pressure pumps.
  5. (figuratively) The supply of additional funding to a person or a business.
    The troubled business received a much-needed cash injection.
  6. (mathematics) A relation on sets (X,Y) that associates each element of Y with at most one element of X.
    Synonym: injective function
  7. (computer security) The insertion of program code into an application, URL, hardware, etc.; especially when malicious or when the target is not designed for such insertion.
    a SQL injection exploit allowing a malicious user to modify a database query
  8. (space science) The act of putting a spacecraft into a particular orbit, especially for changing a stable orbit into a transfer orbit, e.g. trans-lunar injection.
    • 2015, Henry L. Richter, America's Leap Into Space:
      It had been determined that one of the whip turnstile antennas had broken off from Explorer 1 shortly after injection into orbit, so these were eliminated.
  9. (set theory) A function that maps distinct x in the domain to distinct y in the codomain; formally, a fX → Y such that f(a) = f(b) implies a = b for any a, b in the domain.
  10. (medicine) Something injected subcutaneously, intravenously, or intramuscularly by use of a syringe and a needle.
  11. (medicine) Congestion (of a body part, with blood or other fluid), such as hyperemia.
    conjunctival injection
  12. (internal combustion engines) Fuel injection: the pressurized introduction of fuel into a cylinder.
    direct injection
    tuned port injection
  13. (steam engines) The act of throwing cold water into a condenser to produce a vacuum.
  14. (steam engines) The cold water thrown into a condenser to produce a vacuum.


(computer security) Insertion of program code into an application, URL, etc.

Derived terms[edit]

(construction) Terms derived from injection

Related terms[edit]


See also[edit]




Borrowed from Latin iniectiōnem.



injection f (plural injections)

  1. injection

Related terms[edit]


  • Romanian: injecție
  • Turkish: enjeksiyon

Further reading[edit]