ir
ir — noun
1. a written abbreviation for infrared, used to refer to the invisible light waves
a written abbreviation for infrared, used to refer to the invisible light waves just beyond the red end of the visible spectrum, which are felt as heat and are used in remote controls, night vision, thermal imaging, and astronomy.
The remote control sends an IR signal to the television when you press a button.
IR signal = infrared signal from remote control
Security cameras with IR sensors can record clear images even in complete darkness.
Firefighters use IR cameras to find people trapped in smoke-filled buildings during a fire.
The James Webb Space Telescope uses IR sensors to study stars forming inside thick clouds of cosmic dust.
Weather satellites measure IR radiation to track cloud temperatures and predict storms.
The art museum uses IR analysis to find the original sketches hidden beneath the paint.
- infrared
the full form; IR is the abbreviation used in writing
- UV
ultraviolet — the opposite end of the light spectrum
文法句型
IR + [noun]
用法筆記
In scientific and technical writing it is usually written as IR (all capitals). In product labels and informal contexts it may appear as Ir (capital I, lowercase r). Both forms are used interchangeably for 'infrared'.
常見錯誤
2. an abbreviation for Inland Revenue, the UK government department responsible for
an abbreviation for Inland Revenue, the UK government department responsible for collecting taxes such as income tax and corporate tax.
The IR sent Lakshmi a £450 tax refund after she filed her return for the previous year.
IR = Inland Revenue (UK tax authority)
Self-employed workers in Britain must register with the IR and file accounts every year.
The IR website lets taxpayers check their National Insurance payments and update their home address.
Christopher called the IR helpline to ask for an extension on his bakery's January tax payment.
- Inland Revenue
the full name; more formal than IR
- HMRC
the current official name since 2005
文法句型
IR + [verb]
用法筆記
In 2005 the Inland Revenue was merged into HM Revenue and Customs (HMRC), but the abbreviation IR is still used informally to refer to UK tax authorities.
常見錯誤
3. an abbreviation for Internal Revenue, the US government agency that enforces tax
an abbreviation for Internal Revenue, the US government agency that enforces tax laws and collects federal income taxes, formally called the Internal Revenue Service (IRS).
American taxpayers send their federal income tax forms to the IR each year by April 15.
IR = Internal Revenue (US tax collection)
The IR audited the company's records after noticing a mistake in their reported earnings.
Kemi downloaded the IR forms from the IRS site and used a calculator to check her deductions before filing.
The IR offers a free online tool called 'Where's My Refund' that tracks your tax refund status.
- Internal Revenue Service
the full official name of the US tax agency
文法句型
IR + [verb]
用法筆記
IR is an abbreviation for Internal Revenue, but the full agency name is the Internal Revenue Service (IRS). IR alone is less common in modern usage than IRS.
常見錯誤
4. a written abbreviation for information retrieval, meaning the process of finding
a written abbreviation for information retrieval, meaning the process of finding and getting back information from a large collection of data, such as a database or a set of documents.
Priya's PhD research focused on IR systems that help doctors find relevant medical studies quickly.
IR systems = information retrieval systems
The library's IR tool lets students search thousands of academic papers by keyword in seconds.
Yara uses a specialised IR system at her hospital to find patient records by diagnosis code within seconds.
The company hired an IR specialist to build a search tool that finds past orders in two seconds.
- data retrieval
more general term, not specific to search systems
- document retrieval
narrower — focuses on finding documents rather than any data
文法句型
IR + [noun]
用法筆記
IR in this sense is always written in capitals and is most common in academic and technical writing about computer science and library science.
5. the chemical symbol for iridium, a very hard and heavy silver-white metal used i
the chemical symbol for iridium, a very hard and heavy silver-white metal used in spark plugs, electronics, and spacecraft parts.
The periodic table shows Ir for iridium at position 77, between osmium and platinum.
Ir = chemical symbol for iridium on the periodic table
Tamar's necklace was stamped with Ir, meaning the clasp contained a little iridium to make it harder.
The spark plug electrode was coated with Ir, which doubled its lifespan under extreme engine heat.
A one-gram Ir sample costs more than gold because iridium is one of the rarest elements in the crust.
文法句型
Ir + [noun]
用法筆記
Typically written with a capital I and lowercase r (Ir). In chemistry contexts Ir always refers to the element itself, not to a compound.
常見錯誤
6. a short form for intelligence ratio, a number once used to express a person's in
a short form for intelligence ratio, a number once used to express a person's intelligence as a comparison between their mental age and their actual age, similar to an IQ score.
Early intelligence tests calculated an IR by dividing a child's mental age by their actual age and multiplying by 100.
IR = mental age ÷ chronological age × 100
The school psychologist noted that eight-year-old Tanvi's IR of 115 was well above average for her class.
Modern researchers rarely use the IR formula because it gives unreliable results for people over age sixteen.
Researchers in the 1920s used the IR method to rank London schoolchildren by learning ability.
- IQ
the modern replacement; IQ and IR measure similar concepts but use different calculation methods
文法句型
IR + [noun]
IR of [number]
用法筆記
Historical term rarely used in modern psychology. IQ (intelligence quotient) has largely replaced IR in both research and popular use.