Word
acid
US/ˈæsəd/
UK/ˈæsɪd/
Definitions
01chemical substance
B1 · Intermediate Countable noun Science Technical
n. a chemical substance that is usually sour and can sometimes burn your skin.
n. a chemical compound that yields hydrogen ions in water, often characterised by a sour taste and the ability to react with bases to form salts.
日本語:酸※
“The scientist added a few drops of acid to the liquid to see if it would change colour.”
“The laboratory technician carefully measured the concentration of the sulphuric acid before beginning the titration process.”
Usage
In scientific contexts, it is often used as a countable noun to refer to specific types of compounds.
Synonyms
02LSD drug
C1 · Advanced Uncountable noun Slang · Informal
n. a powerful drug that makes people see things that are not there.
n. a slang term for lysergic acid diethylamide (LSD), a potent hallucinogenic drug.
“He claimed that he had a strange experience after taking acid at the festival.”
“The counterculture movement of the 1960s was heavily influenced by the widespread recreational use of acid and other psychedelics.”
Teaching tip
This sense is highly informal and associated with drug culture; learners should use it with caution.
Synonyms
03sour taste
B2 · Upper Intermediate Cooking
adj. having a sharp or sour taste like a lemon.
adj. having a sharp, biting, or sour taste; acidic in flavour.
日本語:酸っぱい※
Español:malhumorado
“The fruit had a very acid taste that made my mouth pucker.”
“The chef balanced the rich, fatty flavours of the duck with an acid reduction of citrus and vinegar.”
04harsh or unkind
C1 · Advanced Literary
adj. describing a way of speaking that is sharp, unkind, or critical.
adj. characterised by a sharp, biting, or sarcastic tone; sour-tempered.
“She made an acid comment about his messy hair.”
“The critic was famous for his acid wit, often dismantling new plays with a single devastating sentence.”
Usage
Usually placed before the noun it describes, such as 'acid wit' or 'acid tongue'.
05music style
C1 · Advanced Music Informal
adj. a style of music that sounds strange or electronic, often linked to dance culture.
adj. denoting a musical genre characterised by repetitive, psychedelic, or distorted electronic sounds.
“The club was playing loud acid house music all night long.”
“The track features the squelching basslines typical of the acid jazz scene that emerged in the late eighties.”
Synonyms
Collocations
Common phrases and expressions where native English speakers use the word “acid” in context.
Verb
01. dissolve in acid
“The metal sample will slowly dissolve in acid during the experiment.”
verb + prep + noun
02. neutralize the acid
“Antacids work by helping to neutralize the acid in your stomach.”
verb + noun
Adjective
03. corrosive acid
“Handle the corrosive acid with extreme care to avoid chemical burns.”
adj + noun
04. dilute acid
“The procedure requires a small amount of dilute acid to trigger the reaction.”
adj + noun
Noun
05. acid rain
“Acid rain has caused significant damage to the local forest ecosystem.”
noun + noun
06. acid reflux
“Eating late at night can often trigger symptoms of acid reflux.”
noun + noun
07. acid test
“The upcoming election will be the acid test for the new government's policies.”
noun + noun
Real-World Examples
“To address this challenge, the researchers developed a platform based on gallic acid, a naturally occurring antioxidant found in plants, fruits and tea leaves.” “Thiamethoxam killed all the workers within about seven days, while boric acid killed roughly 90% within about two weeks.” Etymology
Etymology tree Proto-Indo-European *h₂eḱ-der. Latin aceō Proto-Indo-European *dʰeh₁-der. Latin -idus Latin acidusbor. French acidebor. English acid From French acide, from Latin acidus (“sour, acid”), from aceō (“to be sour”). Doublet of agita.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
NOUN
Related words
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C1 AdvancedIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.7.0–8.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 5.0–5.595–113TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.945–990
- Frequency
- Common
- Level
- C1 · AdvancedOxford
- Updated
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QR code
englishreference.com/q/acid
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「日本語」 data: JMdict (EDRDG), CC BY-SA 4.0
Traducciones: Kaikki.org (Wiktionary), CC BY-SA 4.0