injection

injection — noun

1. a medical procedure in which a liquid medicine or drug is pushed through a hollo

1.nounB1
Definition

a medical procedure in which a liquid medicine or drug is pushed through a hollow needle into a person's skin, muscle, or vein so that it enters the bloodstream or body tissue.

Example

The nurse gave Asher an injection in his upper arm before the flight.

collocation: give + an injection + in/into [body part]

Mayumi needed a daily insulin injection to keep her blood sugar stable.

injection + of [drug] for chronic condition

Common collocations
  • give an injection
  • get an injection
  • receive an injection
  • have an injection
  • insulin injection
  • flu injection
  • a needle injection
  • intravenous injection
Synonyms
  • shot

    informal, very common in American English (e.g., 'a flu shot')

  • jab

    informal, common in British English (e.g., 'a covid jab')

  • vaccination

    narrower meaning — specifically for injections that prevent disease, not for medication in general

  • inoculation

    formal and somewhat dated; refers to introducing a weak form of a disease to build immunity

Grammar Patterns

give/get/receive an injection

injection + of + [medicine/vaccine/insulin]

injection + in/into + [body part]

Usage Note

Commonly used with the verbs 'give', 'get', 'have', or 'receive'. The specific location of the injection is usually introduced by 'in' or 'into' (e.g., 'an injection in the thigh').

Common Mistakes

I got an injection on my arm.
I got an injection in my arm.
Use 'in' or 'into', not 'on', when naming the body part where the needle goes.

2. a large amount of money, investment, or new resources that is put into a company

2.nounB2
Definition

a large amount of money, investment, or new resources that is put into a company, project, or national economy to strengthen it, help it recover from trouble, or make it grow.

Example

The struggling car manufacturer needed an injection of cash to avoid bankruptcy.

collocation: injection of cash

Saira's startup stayed afloat thanks to a capital injection from a group of overseas investors.

collocation: capital injection

Common collocations
  • cash injection
  • capital injection
  • injection of funds
  • injection of cash
  • government injection
  • fresh injection
  • major injection
Synonyms
  • infusion

    very similar meaning, often used for the introduction of money or new ideas into an organisation (e.g., 'a capital infusion')

  • investment

    broader; an injection of money specifically implies an urgent or large-scale investment aimed at rescuing or reviving something

  • stimulus

    usually refers to government spending aimed at the whole economy rather than a single company

Antonyms
  • withdrawal

    the removal of money or resources

  • cut

    a reduction in spending or funding

Grammar Patterns

a(n) [adjective] injection of [money/capital/funds]

injection + into + [company/economy/project]

Usage Note

Commonly followed by 'of' plus the resource being introduced (money, capital, funds, cash, technology). The target recipient is introduced by 'into'. Typically used in business journalism and economic reporting.

Common Mistakes

The company got a money injection from investors.
The company got a cash injection from investors.
'Cash injection' or 'capital injection' is the standard collocation, not 'money injection'.

3. a mechanical process in which a liquid, gas, or fuel is forced under high pressu

3.nounB2
Definition

a mechanical process in which a liquid, gas, or fuel is forced under high pressure into an engine, chamber, or other system so that it mixes with air or reacts to produce power or a desired effect.

Example

Modern cars rely on electronic fuel injection to burn petrol more efficiently.

compound noun: fuel injection

Hiro replaced the faulty injection pump on his diesel truck over the weekend.

compound: injection pump

Common collocations
  • fuel injection
  • injection pump
  • injection nozzle
  • injection system
  • direct injection
  • electronic injection
  • steam injection
Synonyms
  • fuel delivery

    broader term for the process of moving fuel to the engine, not necessarily under pressure

  • spraying

    describes the physical action but is less precise and not a standard technical synonym

Grammar Patterns

fuel injection

injection + pump/valve/nozzle/system

Usage Note

Most commonly encountered in the compound 'fuel injection'. Can be used with other substances (steam, water, air) in industrial or engineering contexts. Frequently modifies other nouns (injection pump, injection valve, injection nozzle).

Common Mistakes

The car has a fuel injection.
The car has fuel injection.
'Fuel injection' is usually an uncountable concept or a modifier, not a countable noun with an article.

Word family

  • inject
    verbB1
  • injectable
    adjectiveB2
  • injector
    nounC1

Synonym discussion

Sense: noun/1

The medical sense of 'injection' is the most general term for putting liquid medicine into the body with a needle. 'Shot' (US informal) is the everyday word people use in casual conversation — you get a 'flu shot' or a 'tetanus shot'. 'Jab' (UK informal) serves the same function in British English ('covid jab', 'flu jab'). 'Vaccination' is more specific: it refers only to injections that protect against disease by building immunity, not to therapeutic drugs like insulin or painkillers. 'Inoculation' is a formal, somewhat dated term for the same idea as vaccination, often associated with historical medical practices. For everyday use, 'injection' and 'shot'/'jab' are freely interchangeable for any needle-based procedure, while 'vaccination' and 'inoculation' are only correct when the purpose is disease prevention.

shot ↗jabvaccinationinoculation

Common collocations

Nouns

Adverbs

  • intravenously
  • intramuscularly
  • subcutaneously
  • directly

Phrases

  • give an injection
  • get an injection
  • receive an injection
  • have an injection
  • injection of capital
  • fuel injection system
  • cash injection

Prepositions

Etymology

LatinFrenchEnglish

The word 'injection' comes from Latin 'injectio' (a throwing in), based on 'inicere' — 'in-' (into) + 'jacere' (to throw). It entered English in the 1400s through medical French, originally referring to the medical act of introducing liquid into the body. The financial and mechanical meanings appeared later as people used the same 'throwing in' image to describe introducing money into a business or fuel into an engine.