# acid

/ˈæsəd/ (US) · /ˈæsɪd/ (UK)

Source: https://englishreference.com/word/acid
Updated: 2026-07-22

## Senses

### 1. chemical substance

noun · CEFR B1 · Technical

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

For teachers: 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.

- 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.

### 2. LSD drug

noun · CEFR C1 · Slang · Informal

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

For teachers: 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.

### 3. sour taste

adjective · CEFR B2

having a sharp or sour taste like a lemon.

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

- 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.

### 4. harsh or unkind

adjective · CEFR C1 · Literary

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

For teachers: 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'.

### 5. music style

adjective · CEFR C1 · Informal

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

For teachers: 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.

## Examples

- The acid in the lemon makes the juice taste very sour.
- Scientists wear protective gloves when handling strong acid to prevent chemical burns on their skin.
- The gradual erosion of the limestone statues was accelerated by acid rain, which reacts with the calcium carbonate to dissolve the fine details of the carvings.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.