# injection

Pronunciation: US say "in-JEK-shuhn" /ɪnˈd͡ʒɛk.ʃən/; UK

## Noun

1. A substance put into the body through a syringe and needle, under the skin, into a vein, or into a muscle.
   - Simple: A dose of medicine pushed into the body through a needle.
   - _The clinic offers flu shots as a quick injection in the upper arm._
   - _Doctors prescribed daily injections to keep her blood sugar under control._
2. The act of forcing a substance into something, or the substance that is forced in.
   - Simple: The act of pushing a substance into something, or the substance that goes in.
   - _The injection of cooling fluid stabilized the reactor's temperature._
   - _Engineers timed the injection of gas into the chamber precisely._
3. A supply of additional funding provided to a person or a business.
   - Simple: Extra money given to a person or business to help it keep going.
   - _The startup survived thanks to a timely injection of venture capital._
   - _Government injections of funding kept the rural hospitals running._
4. The forcing of fuel into an engine cylinder under high pressure.
   - Simple: A way of pushing fuel into an engine under pressure.
   - _Direct injection sprays fuel straight into the combustion chamber._
   - _Engineers tuned the injection to improve fuel economy._
5. The insertion of code into an application, web address, device, or similar target, especially maliciously or where the target was never meant to accept it.
   - Simple: The act of putting code into a program or website, often to attack it.
   - _SQL injection let the attacker read the entire customer database._
   - _Developers test their forms to block any injection of harmful code._
6. The act of placing a spacecraft into a particular orbit, especially to change a stable orbit into a transfer orbit.
   - Simple: The act of putting a spacecraft onto a planned path through space.
   - _Trans-lunar injection sent the spacecraft out of Earth orbit toward the Moon._
   - _A precise injection placed the satellite in its intended geostationary orbit._
7. An accumulation of blood or other fluid that congests a part of the body, as in hyperemia.
   - Simple: A buildup of blood or fluid in part of the body.
   - _The exam revealed conjunctival injection consistent with irritation._
   - _Marked injection of the tissue pointed to underlying inflammation._
8. The use of high-pressure pumps to force materials such as concrete grout or gravel into place.
   - Simple: The act of pushing materials like concrete or gravel in using high-pressure pumps.
   - _Pressure grouting relies on the injection of cement slurry into voids beneath the slab._
   - _Engineers stabilized the soft soil through the injection of grout under high pressure._
9. A function that maps distinct inputs to distinct outputs, so that no two different inputs produce the same value.
   - Simple: A rule that sends each input to its own different output, with no two inputs sharing one.
   - _The function f(x) = 2x is an injection on the real numbers._
   - _To prove a map is an injection, show that equal outputs force equal inputs._
10. A relation between sets X and Y under which no element of Y is linked to more than one element of X.
   - Simple: A pairing between two sets where each item in one set links to at most one item in the other.
   - _Stated as a relation, an injection links each element of the codomain to no more than one source._
   - _They modeled the assignment as an injection between the two finite sets._
11. A specimen that has been prepared by means of injection, with its vessels filled to show fine structure.
   - Simple: A sample for study made by filling its vessels with a special material.
   - _The anatomy collection featured a remarkable injection of the kidney's vascular network._
   - _Each injection was prepared by filling the vessels with colored resin before dissection._
12. For a coproduct of two objects, a morphism carrying either component into the coproduct.
   - Simple: A way of fitting one of two combined pieces into the whole they form.
   - _In the disjoint union, each injection embeds a summand into the coproduct._
   - _The coproduct comes with an injection from each of its two components._
13. The throwing of cold water into a condenser in order to produce a vacuum.
   - Simple: The act of throwing cold water into a condenser to make a vacuum.
   - _The old engine used injection to condense its spent steam back into water._
   - _Operators controlled the injection carefully to keep the vacuum steady._
14. Cold water sprayed into a condenser so that the steam condenses and a vacuum forms.
   - Simple: The cold water thrown into a condenser to make a vacuum.
   - _The condenser filled with injection until the spent steam collapsed into water._
   - _Warm injection drained from the condenser back into the hot well._

## Origin

This word was borrowed from Middle French injection, itself from Latin iniectio. The mathematical sense comes from French injection, introduced by Nicolas Bourbaki in their treatise Éléments de mathématique. It is equivalent to inject plus the suffix -ion.

Source: DictionaryAI, https://dictionaryai.com/define/injection (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).