What does "acid" mean?

1. (chemical substance) a chemical substance that is usually sour and can sometimes burn your skin. 2. (LSD drug) a powerful drug that makes people see things that are not there. 3. (sour taste) having a sharp or sour taste like a lemon. 4. (harsh or unkind) describing a way of speaking that is sharp, unkind, or critical. 5. (music style) a style of music that sounds strange or electronic, often linked to dance culture.

How do you use "acid"?

In scientific contexts, it is often used as a countable noun to refer to specific types of compounds. Usually placed before the noun it describes, such as 'acid wit' or 'acid tongue'.

acid

n. · adj.

US //ˈæsəd// UK //ˈæsɪd// acid

1 chemical substance (n.)
B1 Intermediate Technical Science

a chemical substance that is usually sour and can sometimes burn your skin.

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.

Example

The scientist added a few drops of acid to the liquid to see if it would change colour.

Example

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.
- chemical
- base
- alkali
2 LSD drug (n.)
C1 Advanced Slang Informal

a powerful drug that makes people see things that are not there.

a slang term for lysergic acid diethylamide (LSD), a potent hallucinogenic drug.

Example

He claimed that he had a strange experience after taking acid at the festival.

Example

The counterculture movement of the 1960s was heavily influenced by the widespread recreational use of acid and other psychedelics.

Teacher's tip

This sense is highly informal and associated with drug culture; learners should use it with caution.
- LSD
- hallucinogen

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3 sour taste (adj.)
B2 Upper Intermediate Cooking

having a sharp or sour taste like a lemon.

having a sharp, biting, or sour taste; acidic in flavour.

Example

The fruit had a very acid taste that made my mouth pucker.

Example

The chef balanced the rich, fatty flavours of the duck with an acid reduction of citrus and vinegar.
- sweet
- bland
4 harsh or unkind (adj.)
C1 Advanced Literary

describing a way of speaking that is sharp, unkind, or critical.

characterised by a sharp, biting, or sarcastic tone; sour-tempered.

Example

She made an acid comment about his messy hair.

Example

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'.
- sarcastic
- biting
- acerbic
- kind
- sweet
5 music style (adj.)
C1 Advanced Informal Music

a style of music that sounds strange or electronic, often linked to dance culture.

denoting a musical genre characterised by repetitive, psychedelic, or distorted electronic sounds.

Example

The club was playing loud acid house music all night long.

Example

The track features the squelching basslines typical of the acid jazz scene that emerged in the late eighties.
- psychedelic

Origin

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.